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<head><meta charset="utf-8"><title>general discussion · t-compiler/wg-nll · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/index.html">t-compiler/wg-nll</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html">general discussion</a></h3>

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<a name="126057957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126057957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Welcome Bot <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126057957">(May 03 2018 at 18:21)</a>:</h4>
<p>Welcome to <a class="stream" data-stream-id="122657" href="/#narrow/stream/122657-wg-nll">#wg-nll</a>.</p>
<p><strong>Description</strong>: Non-lexical lifetimes working group</p>



<a name="126058505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126058505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126058505">(May 03 2018 at 18:33)</a>:</h4>
<p><span class="user-mention" data-user-id="116013">@Douglas Campos</span> testing, testing</p>



<a name="126060618"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126060618" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126060618">(May 03 2018 at 19:12)</a>:</h4>
<p>here!</p>



<a name="126060680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126060680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126060680">(May 03 2018 at 19:13)</a>:</h4>
<blockquote>
<p><span class="user-mention" data-user-id="116013">@Douglas Campos</span> testing, testing</p>
</blockquote>
<p>testing a reply</p>



<a name="126096722"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096722" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096722">(May 04 2018 at 13:51)</a>:</h4>
<p>I invited <span class="user-mention" data-user-id="116083">@Felix S Klock II</span> to join =)</p>



<a name="126096847"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096847" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096847">(May 04 2018 at 13:54)</a>:</h4>
<p>this is Felix's attempt to send a message that all the WG-nll people can see!</p>



<a name="126096868"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096868" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096868">(May 04 2018 at 13:55)</a>:</h4>
<p>I saw it!</p>



<a name="126096932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096932">(May 04 2018 at 13:57)</a>:</h4>
<p><span class="emoji emoji-1f64c" title="raised hands">:raised_hands:</span></p>



<a name="126096977"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096977" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096977">(May 04 2018 at 13:58)</a>:</h4>
<p>the weird thing is that when <span class="user-mention" data-user-id="116083">@Felix S Klock II</span> joined, he didn't immediately see the wg-nll stream on the left</p>



<a name="126096987"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096987" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096987">(May 04 2018 at 13:59)</a>:</h4>
<p>this streams concept is a blessing and a curse<br>
too confusing tbh</p>



<a name="126096990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096990">(May 04 2018 at 13:59)</a>:</h4>
<p>I think you are referring to the "threads" concept</p>



<a name="126096993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096993">(May 04 2018 at 13:59)</a>:</h4>
<p>shades of Google Wave</p>



<a name="126096996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096996">(May 04 2018 at 13:59)</a>:</h4>
<p>I think the problem <span class="user-mention" data-user-id="116083">@Felix S Klock II</span> had was that the set of streams defaults to showing you the streams you are subscribed too</p>



<a name="126096999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126096999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126096999">(May 04 2018 at 13:59)</a>:</h4>
<p>which, I guess, makes sense</p>



<a name="126097000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097000">(May 04 2018 at 13:59)</a>:</h4>
<p>but somehow ran counter to my expectations</p>



<a name="126097001"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097001" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097001">(May 04 2018 at 13:59)</a>:</h4>
<p>it's google wave dejavu's all over again</p>



<a name="126097050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097050">(May 04 2018 at 14:00)</a>:</h4>
<p>that is, it's not like (e.g.) gitter shows you all the rooms that exist</p>



<a name="126097051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097051">(May 04 2018 at 14:00)</a>:</h4>
<p>or IRC</p>



<a name="126097075"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097075">(May 04 2018 at 14:00)</a>:</h4>
<p>one weird thing -- I've not found any easy way to see which users are subscribed to a stream? Or maybe that is indicated by the "Users" listing on the RHS</p>



<a name="126097091"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097091" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097091">(May 04 2018 at 14:01)</a>:</h4>
<p>no, it doesn't seem to be</p>



<a name="126097093"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097093" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097093">(May 04 2018 at 14:01)</a>:</h4>
<p>no, RHS is all users</p>



<a name="126097101"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097101" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097101">(May 04 2018 at 14:01)</a>:</h4>
<p>weird</p>



<a name="126097142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097142">(May 04 2018 at 14:02)</a>:</h4>
<p>(though, to be clear, an "all users" listing is actually a really useful thing to have —I get annoyed a lot on IRC when I have to jump from room to room to find someone's nick that I can't <em>quite</em> remember)</p>



<a name="126097213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097213">(May 04 2018 at 14:04)</a>:</h4>
<p><span class="user-mention" data-user-id="116013">@Douglas Campos</span> oh I missed that you said you had 45 minutes to hack</p>



<a name="126097215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097215">(May 04 2018 at 14:04)</a>:</h4>
<p>I guess it's less now</p>



<a name="126097217"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097217" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097217">(May 04 2018 at 14:04)</a>:</h4>
<p>I have a suggestion :P</p>



<a name="126097219"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097219" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097219">(May 04 2018 at 14:04)</a>:</h4>
<p>go for it</p>



<a name="126097225"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097225" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097225">(May 04 2018 at 14:05)</a>:</h4>
<p>I will push a commit real quick to my repo one sec</p>



<a name="126097232"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097232" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097232">(May 04 2018 at 14:05)</a>:</h4>
<p>ok, I made a branch called <code>stats</code></p>



<a name="126097287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097287">(May 04 2018 at 14:06)</a>:</h4>
<p>I was going to integrate <a href="https://github.com/fitzgen/histo" target="_blank" title="https://github.com/fitzgen/histo">the histo crate</a></p>



<a name="126097290"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097290" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097290">(May 04 2018 at 14:06)</a>:</h4>
<p>and use it to dump various bits of data</p>



<a name="126097312"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097312" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097312">(May 04 2018 at 14:07)</a>:</h4>
<p>in particular, I'd like to see:</p>
<ul>
<li>the in- and out-degree of nodes plotted in histogram format</li>
</ul>
<p>once that works:</p>
<ul>
<li>the option to limit this to the in- and out-degree of regions that are going dead in the next node</li>
</ul>



<a name="126097317"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097317" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097317">(May 04 2018 at 14:07)</a>:</h4>
<p>the main changes in those branch are that I added a way of iterating over all the <code>r1 &lt;= r2</code> edges after the fact (regardless of where they occur)</p>



<a name="126097322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097322">(May 04 2018 at 14:07)</a>:</h4>
<p>I'm going to investigate something else for a bit so I won't touch it anymore</p>



<a name="126097371"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097371" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097371">(May 04 2018 at 14:08)</a>:</h4>
<p>here is <a href="https://github.com/nikomatsakis/borrow-check/blob/0fa65d0b23555df97b3f16e6f7be544f272cb53e/src/cli.rs#L91-L94" target="_blank" title="https://github.com/nikomatsakis/borrow-check/blob/0fa65d0b23555df97b3f16e6f7be544f272cb53e/src/cli.rs#L91-L94">where I was adding a loop</a></p>



<a name="126097611"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097611" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097611">(May 04 2018 at 14:14)</a>:</h4>
<p>pulling the branch now</p>



<a name="126097631"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097631" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097631">(May 04 2018 at 14:15)</a>:</h4>
<p>not sure if you got my message later, but I couldn't assign issues on the borrow-check repo</p>



<a name="126097710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097710">(May 04 2018 at 14:16)</a>:</h4>
<p>I think I invited you to the WG-compiler-nll team on rust-lang-nursery, no?</p>



<a name="126097729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097729">(May 04 2018 at 14:17)</a>:</h4>
<p>yes, I did -- <span class="user-mention" data-user-id="116013">@Douglas Campos</span> you have to accept your invitation</p>



<a name="126097804"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097804" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097804">(May 04 2018 at 14:18)</a>:</h4>
<p>found the invitation, it was buried with rust-lang github notifications <span class="emoji emoji-1f602" title="joy">:joy:</span></p>



<a name="126097806"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097806" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097806">(May 04 2018 at 14:18)</a>:</h4>
<p>one thing I don't love about zulip -- it doesn't seem to have the "nickname" concept?</p>



<a name="126097810"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097810" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097810">(May 04 2018 at 14:18)</a>:</h4>
<p>I guess you have to change your "real name"</p>



<a name="126097814"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097814" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097814">(May 04 2018 at 14:18)</a>:</h4>
<p>I like "nicks" :)</p>



<a name="126097815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126097815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126097815">(May 04 2018 at 14:19)</a>:</h4>
<p>yea, nicks are great</p>



<a name="126098402"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098402" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098402">(May 04 2018 at 14:33)</a>:</h4>
<p>/me brings back his nick by force</p>



<a name="126098495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098495">(May 04 2018 at 14:34)</a>:</h4>
<p>/me breaks <span class="user-mention" data-user-id="116009">@Nicholas Matsakis</span> 's previous @-references to Felix S Klock II</p>



<a name="126098502"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098502" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098502">(May 04 2018 at 14:34)</a>:</h4>
<p>(apparently they have not added alpha-renaming as a "feature" here.)</p>



<a name="126098515"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098515" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098515">(May 04 2018 at 14:35)</a>:</h4>
<p>oh, wait, they <em>aren't</em> broken! You can still click them!</p>



<a name="126098567"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098567" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098567">(May 04 2018 at 14:36)</a>:</h4>
<p>nice</p>



<a name="126098570"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098570" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098570">(May 04 2018 at 14:36)</a>:</h4>
<p>sometimes it doesn't seem to "scroll down" and I have to do it manually. that is odd.</p>



<a name="126098575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098575">(May 04 2018 at 14:36)</a>:</h4>
<p>I'm adopting a nick too :)</p>



<a name="126098634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098634">(May 04 2018 at 14:38)</a>:</h4>
<p>hey <span class="user-mention" data-user-id="116009">@nikomatsakis</span> do you want to have another r? on rust-lang/rust#49870, or shall I just <code>r=nikomatsakis</code> it based on your earlier "r+ once nits addressed" ? The subsequent changes were a <em>little</em> more involved due to arielb1 feedback, but it was still pretty straight-forward...</p>



<a name="126098640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098640">(May 04 2018 at 14:38)</a>:</h4>
<p>oh no, how do I link github issues here???</p>



<a name="126098644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098644">(May 04 2018 at 14:38)</a>:</h4>
<p>oh geez! that's a fail</p>



<a name="126098648"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098648" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098648">(May 04 2018 at 14:38)</a>:</h4>
<p>there's probably a bot or integration</p>



<a name="126098657"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098657" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098657">(May 04 2018 at 14:39)</a>:</h4>
<p>I was going to ask, <span class="user-mention" data-user-id="*">@all</span>, whether we ought to really "try" this experiment or not...</p>



<a name="126098661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098661">(May 04 2018 at 14:39)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> if you're focusing on the stream it scrolls down - if you lose focus it stays put so you don't miss where you left off</p>



<a name="126098665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098665">(May 04 2018 at 14:39)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> i don't feel the need to review 49870</p>



<a name="126098666"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098666" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098666">(May 04 2018 at 14:39)</a>:</h4>
<p><span class="emoji emoji-2611" title="ballot box with check">:ballot_box_with_check:</span></p>



<a name="126098669"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098669" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098669">(May 04 2018 at 14:39)</a>:</h4>
<p>hate to admit, but I miss gitter - I just wish it worked well</p>



<a name="126098726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098726">(May 04 2018 at 14:40)</a>:</h4>
<p>there is this bot: <a href="https://zulipchat.com/integrations/doc/github_detail" target="_blank" title="https://zulipchat.com/integrations/doc/github_detail">https://zulipchat.com/integrations/doc/github_detail</a></p>



<a name="126098730"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098730" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098730">(May 04 2018 at 14:40)</a>:</h4>
<p>I agree that gitter feels in some ways closer to what I would hope for</p>



<a name="126098731"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098731" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098731">(May 04 2018 at 14:40)</a>:</h4>
<p>there's just a few tweaks ... well, that and receiving messages</p>



<a name="126098748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098748">(May 04 2018 at 14:41)</a>:</h4>
<p>I filed a bug about the gitter notificaitons going missing</p>



<a name="126098751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098751">(May 04 2018 at 14:41)</a>:</h4>
<p><a href="https://gitlab.com/gitlab-org/gitter/webapp/issues/1894" target="_blank" title="https://gitlab.com/gitlab-org/gitter/webapp/issues/1894">https://gitlab.com/gitlab-org/gitter/webapp/issues/1894</a></p>



<a name="126098756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098756">(May 04 2018 at 14:41)</a>:</h4>
<p>it annoys me that they are not treating this like "def con zero" :)</p>



<a name="126098760"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098760" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098760">(May 04 2018 at 14:41)</a>:</h4>
<p>maybe y'all want to weigh in there</p>



<a name="126098765"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098765" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098765">(May 04 2018 at 14:41)</a>:</h4>
<p>"they" is perhaps just 1 maintainer, I don't know</p>



<a name="126098811"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098811" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098811">(May 04 2018 at 14:42)</a>:</h4>
<p>though gitter has had other flaws (missing notifications, bad android app, etc) for a long time :(</p>



<a name="126098994"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126098994" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126098994">(May 04 2018 at 14:47)</a>:</h4>
<p>long time = one week (?)</p>



<a name="126099050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126099050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126099050">(May 04 2018 at 14:48)</a>:</h4>
<p>way more than one week</p>



<a name="126099176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126099176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126099176">(May 04 2018 at 14:51)</a>:</h4>
<p>somehow didn't realize gitter's missing notifications were going on longer than maybe 2 weeks. But I can believe it.</p>



<a name="126099291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126099291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126099291">(May 04 2018 at 14:54)</a>:</h4>
<p>I've setup the irc bridge solely for not missing mentions<br>
then the irc bridge broke <span class="emoji emoji-1f937" title="shrug">:shrug:</span></p>



<a name="126099687"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126099687" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126099687">(May 04 2018 at 15:04)</a>:</h4>
<p>yeah, lots of people complain about it. Running the app, things mostly worked for me, but I've setup "Backup channels" for reaching people I communicate with regularly, in part for this reason.</p>



<a name="126113805"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113805" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113805">(May 04 2018 at 21:04)</a>:</h4>
<p>/me waves to <span class="user-mention" data-user-id="116106">@Reed Koser</span></p>



<a name="126113830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113830">(May 04 2018 at 21:05)</a>:</h4>
<p>hello. You're right, this is a... different approach to chat. I can see it being cool though</p>



<a name="126113836"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113836" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113836">(May 04 2018 at 21:05)</a>:</h4>
<p>e.g. new threads for weekly meetings etc.</p>



<a name="126113897"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113897" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113897">(May 04 2018 at 21:06)</a>:</h4>
<p>yes -- threads have a lot of interesting potential</p>



<a name="126113904"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113904" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113904">(May 04 2018 at 21:06)</a>:</h4>
<p>both for good and ill :)</p>



<a name="126113929"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113929" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113929">(May 04 2018 at 21:07)</a>:</h4>
<p>gah, I guess I have to go home now</p>



<a name="126113998"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126113998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126113998">(May 04 2018 at 21:08)</a>:</h4>
<p>let's see if i'm doing this right</p>



<a name="126114013"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114013" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114013">(May 04 2018 at 21:08)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="kd">let</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Box</span>::<span class="n">new</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span><span class="w"></span>
</pre></div>



<a name="126114014"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114014" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114014">(May 04 2018 at 21:08)</a>:</h4>
<p>Yep, seems like.</p>



<a name="126114048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114048">(May 04 2018 at 21:09)</a>:</h4>
<p>I do quite like this.</p>



<a name="126114100"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114100" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114100">(May 04 2018 at 21:10)</a>:</h4>
<p>Oops. I made a new chat.</p>



<a name="126114107"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114107" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114107">(May 04 2018 at 21:10)</a>:</h4>
<p>just a bit annoying that you need to click reply before you can type, but otherwise it feels ok for now</p>



<a name="126114128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114128">(May 04 2018 at 21:11)</a>:</h4>
<p>let's see how GH links look like: <a href="https://github.com/rust-lang-nursery/borrow-check/issues/6" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/issues/6">https://github.com/rust-lang-nursery/borrow-check/issues/6</a></p>



<a name="126114136"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114136" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114136">(May 04 2018 at 21:11)</a>:</h4>
<p>just like any other</p>



<a name="126114137"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114137" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114137">(May 04 2018 at 21:11)</a>:</h4>
<p>We kinda need a github bot</p>



<a name="126114211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114211">(May 04 2018 at 21:12)</a>:</h4>
<p>yeah there is a standard one I think</p>



<a name="126114216"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114216" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114216">(May 04 2018 at 21:12)</a>:</h4>
<p>I gotta run now but maybe we can mess around with configing later</p>



<a name="126114225"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114225" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114225">(May 04 2018 at 21:12)</a>:</h4>
<p>I know that Zulip is an open source project that has a similar welcoming attitude to contributors as Rust does. So there may be opportunity to tweak little things if we find the need. I think Gitter is too, granted.</p>



<a name="126114294"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114294" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114294">(May 04 2018 at 21:14)</a>:</h4>
<p>Clicking on a message should let you reply directly to it, and you can keep sending messages in the same thread with just control-enter I think</p>



<a name="126114321"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114321" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114321">(May 04 2018 at 21:15)</a>:</h4>
<p>The app is quite nice, you can just click into a topic and it's like a normal chat.</p>



<a name="126114366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114366">(May 04 2018 at 21:16)</a>:</h4>
<p><a href="https://zulipchat.com/for/open-source/" target="_blank" title="https://zulipchat.com/for/open-source/">https://zulipchat.com/for/open-source/</a> is quite good.</p>



<a name="126114621"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114621" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114621">(May 04 2018 at 21:23)</a>:</h4>
<p>Looks like <span class="user-mention" data-user-id="116009">@nikomatsakis</span> just needs to add something like <code>(?P&lt;org&gt;[\w\-]+)\/(?P&lt;project&gt;[\w\-]+)#(?P&lt;issue&gt;[\d]+)</code>  with a URL format string <code>https://github.com/%(org)/%(project)/issues/%(issue)</code>into the URL filter list</p>



<a name="126114629"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114629" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114629">(May 04 2018 at 21:23)</a>:</h4>
<p>There's a GitHub Details integration that does that.</p>



<a name="126114778"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126114778" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126114778">(May 04 2018 at 21:27)</a>:</h4>
<p>oh true. I got to practice my regex-foo at least ;)</p>



<a name="126115908"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126115908" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Chris Vittal <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126115908">(May 04 2018 at 21:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> I have an updated relation branch, I also rebased it from master. Do you mind if I force push to your repo?</p>



<a name="126134456"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126134456" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126134456">(May 05 2018 at 09:05)</a>:</h4>
<p><span class="user-mention" data-user-id="116110">@Chris Vittal</span> no, go for it</p>



<a name="126173176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126173176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126173176">(May 06 2018 at 11:07)</a>:</h4>
<p><span class="user-mention" data-user-id="116109">@Vytautas Astrauskas</span> regarding <a href="https://gitter.im/rust-impl-period/WG-compiler-nll?at=5aedf197da323a7c04fc6cee" target="_blank" title="https://gitter.im/rust-impl-period/WG-compiler-nll?at=5aedf197da323a7c04fc6cee">your question from gitter</a>, I was exploring in a branch the idea of doing renaming and trying to avoid removing subset edges when propagating. Unfortunately, it caused Issue 47680 to stop compiling, at least the way that I did it. If you recall that example looks something like this:</p>
<div class="codehilite"><pre><span></span><span class="k">loop</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">  </span><span class="k">match</span><span class="w"> </span><span class="n">temp</span><span class="p">.</span><span class="n">foo</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="c1">// creates a mutable loan L0 of `temp`</span>
<span class="w">  </span><span class="nb">Some</span><span class="p">(</span><span class="n">v</span><span class="p">)</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="n">temp</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">v</span><span class="p">,</span><span class="w"></span>
<span class="w">  </span><span class="nb">None</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="p">(),</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<p>In this case, along the <code>Some</code> path, we were linking the region for the call to <code>foo</code> with the regions in <code>temp</code> and then propagating those subset relations forward. They were no killed when <code>v</code> goes dead. Then we were adding the loan at the point where <code>foo</code> is called -- this loan gets killed on the <code>Some</code> path, but not the <code>None</code> path, and hence we had a path where <code>temp</code> was considered borrowed. Sorry this explanation is short, I'm in the middle of something else -- I should try to do a kind of canonical write-up of this example, though, as I think it illustrates some of the more subtle points.</p>
<p>That said, this (which you wrote on gitter):</p>
<blockquote>
<p>I have checked the clap-rs example and found that it has 50 000 program points with at most 60 live regions per program point.</p>
</blockquote>
<p>was roughly what I expected to see (lots of points, lots of regions, but few that are <strong>actually live</strong> at any given point). If I recall, that example has ~20,000 regions. That I think <em>should</em> offer us a lot of opportunity. I confess though I didn't quite understand this part:</p>
<blockquote>
<p>Assuming we can find a way to implement subset(R1, R2, P) with a query complexity of log(N), computing requires for all program points would require 50 000 * 60 * log(1000 000, 2) &lt; 60 000 000 operations.</p>
</blockquote>
<p>I'm not sure if that is supposed to be a lot or a little or <em>quite</em> where those numbers came from... I guess that's just a max number of subsets or something?</p>



<a name="126209136"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126209136" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126209136">(May 07 2018 at 10:10)</a>:</h4>
<p>Thank you once again for pointing out this example! I am trying to understand what is the problem with it.</p>
<blockquote>
<p>That said, this (which you wrote on gitter):</p>
<blockquote>
<p>I have checked the clap-rs example and found that it has 50 000 program points with at most 60 live regions per program point.</p>
</blockquote>
<p>was roughly what I expected to see (lots of points, lots of regions, but few that are <strong>actually live</strong> at any given point). If I recall, that example has ~20,000 regions. That I think <em>should</em> offer us a lot of opportunity.</p>
</blockquote>
<p>One more observation: I think that we care not about live regions, but about the regions that die at a specific program point because these are the ones that make live loans dead. In other words, we could check what regions died at a specific program point and what loans died as a result of that instead of checking for each loan if it is still alive. Is this idea clear, or should I elaborate? (Note: I have no clue if it is possible to implement this with Datalog, but it should not be too dificult if we use a custom flow analysis.) I would expect this to give around 10x speedup.</p>
<blockquote>
<p>I confess though I didn't quite understand this part:</p>
<blockquote>
<p>Assuming we can find a way to implement subset(R1, R2, P) with a query complexity of log(N), computing requires for all program points would require 50 000 * 60 * log(1000 000, 2) &lt; 60 000 000 operations.</p>
</blockquote>
<p>I'm not sure if that is supposed to be a lot or a little or <em>quite</em> where those numbers came from... I guess that's just a max number of subsets or something?</p>
</blockquote>
<p>These numbers are from the <code>clap-rs</code> example:</p>
<ul>
<li><code>50 000</code> – the number of program points;</li>
<li><code>60</code> – the upper bound on the number of loans that are live at a specific program point;</li>
<li><code>1000 000</code> – the upper bound on base subset relations;</li>
<li><code>log(N, 2)</code> – hypothesized query complexity of the subset relation (this is an assumption that I <strong>still need to check</strong>);</li>
<li><code>30</code> – the upper bound on loans that are live at a specific program point (this number was missing in the text you cite);</li>
</ul>
<p>If we multiply all this, we get <code>&lt; 1800 000 000</code> operations to borrow check the <code>clap-rs</code> example. This should be around several seconds with a decent CPU. My gut feeling is that by tracking only the regions that die, we could get an additional 10x speedup that should push this below 1 second.</p>



<a name="126218177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218177">(May 07 2018 at 14:43)</a>:</h4>
<p>So while working on <a href="https://github.com/rust-lang/rust/issues/27282" target="_blank" title="https://github.com/rust-lang/rust/issues/27282">https://github.com/rust-lang/rust/issues/27282</a> and generalizing my solution to also fix <a href="https://github.com/rust-lang/rfcs/issues/1006" target="_blank" title="https://github.com/rust-lang/rfcs/issues/1006">https://github.com/rust-lang/rfcs/issues/1006</a> , I found this line of code:</p>



<a name="126218196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218196">(May 07 2018 at 14:43)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/blob/master/src/librustc_mir/borrow_check/mod.rs#L1714" target="_blank" title="https://github.com/rust-lang/rust/blob/master/src/librustc_mir/borrow_check/mod.rs#L1714">https://github.com/rust-lang/rust/blob/master/src/librustc_mir/borrow_check/mod.rs#L1714</a></p>



<a name="126218242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218242">(May 07 2018 at 14:44)</a>:</h4>
<p>which looks like this </p>
<div class="codehilite"><pre><span></span><span class="k">if</span><span class="w"> </span><span class="kd">let</span><span class="w"> </span><span class="nb">Err</span><span class="p">(</span><span class="n">_place_err</span><span class="p">)</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">is_mutable</span><span class="p">(</span><span class="n">place</span><span class="p">,</span><span class="w"> </span><span class="n">LocalMutationIsAllowed</span>::<span class="n">Yes</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">span_bug</span><span class="o">!</span><span class="p">(</span><span class="n">span</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;&amp;unique borrow for {:?} should not fail&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">place</span><span class="p">);</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="126218271"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218271" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218271">(May 07 2018 at 14:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> ok...</p>



<a name="126218272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218272">(May 07 2018 at 14:45)</a>:</h4>
<p>That is, we seem to be able to assume in the current rustc that the borrow-checker will never encounter an attempt to mutate through a unique borrow. But in my case, its a unique borrow of one of my funny implicitly injected shared-borrows</p>



<a name="126218315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218315">(May 07 2018 at 14:46)</a>:</h4>
<p>(well, I should probably double-check that claim by actually looking at the generated MIR...)</p>



<a name="126218316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218316">(May 07 2018 at 14:46)</a>:</h4>
<p>I wonder why we think we can assume that</p>



<a name="126218318"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218318" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218318">(May 07 2018 at 14:46)</a>:</h4>
<p>not entirely obvious to me</p>



<a name="126218320"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218320" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218320">(May 07 2018 at 14:46)</a>:</h4>
<p>Right, that was my question</p>



<a name="126218322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218322">(May 07 2018 at 14:46)</a>:</h4>
<p>E.g. the obvious fix to me was to merge this match arm with the one below it</p>



<a name="126218326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218326">(May 07 2018 at 14:46)</a>:</h4>
<p>which instead of ICE'ing, reports the error</p>



<a name="126218424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126218424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126218424">(May 07 2018 at 14:49)</a>:</h4>
<p><span class="user-mention" data-user-id="116109">@Vytautas Astrauskas</span> I agree that the number of dead regions is ok. I've not had time to process the rest of your message "in detail", but skimming it, it makes sense.</p>



<a name="126227000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126227000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126227000">(May 07 2018 at 18:23)</a>:</h4>
<p>( JFYI, I've also been experimenting with Discord, and I have to say I think it is probably "The Future" more so than Zulip. It might make sense to just jump over there, even though we just got here. )</p>



<a name="126229573"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126229573" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126229573">(May 07 2018 at 19:24)</a>:</h4>
<p>I think I finally understand why <code>region_live_at</code> is needed in the <code>subset3</code> rule. Without it, we get a cyclic <code>subset</code> relation among the regions, which causes the variable <code>temp</code> to keep alive the region associated with <code>v</code> on the <code>None</code> branch. Nice example. <span class="emoji emoji-263a" title="relaxed">:relaxed:</span></p>



<a name="126229723"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126229723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126229723">(May 07 2018 at 19:29)</a>:</h4>
<p>yes, that's it</p>



<a name="126230279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230279">(May 07 2018 at 19:46)</a>:</h4>
<p>is there a discord room already?</p>



<a name="126230580"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230580" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230580">(May 07 2018 at 19:55)</a>:</h4>
<p>Yes. To be honest, I was holding off, but I don't know why, I think we should just up and move</p>



<a name="126230583"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230583" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230583">(May 07 2018 at 19:55)</a>:</h4>
<p>it seems pretty clear that Discord is way more accessible</p>



<a name="126230588"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230588" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230588">(May 07 2018 at 19:55)</a>:</h4>
<p>even though I kind of like zulip :)</p>



<a name="126230636"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230636" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230636">(May 07 2018 at 19:56)</a>:</h4>
<p><a href="http://discord.gg/rust-lang" target="_blank" title="http://discord.gg/rust-lang">discord.gg/rust-lang</a> -- I'll make an NLL room there</p>



<a name="126230664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230664">(May 07 2018 at 19:57)</a>:</h4>
<p>I feel like the benefits of Zulip appear more at scale than with the smaller chats we're currently having.</p>



<a name="126230670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230670">(May 07 2018 at 19:57)</a>:</h4>
<p>It'd be particularly useful with the many concurrent conversations that can happen in #rustc on IRC.</p>



<a name="126230671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230671">(May 07 2018 at 19:57)</a>:</h4>
<p>perhaps so</p>



<a name="126230676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230676">(May 07 2018 at 19:57)</a>:</h4>
<p>yeah -- I can definitely imagine the threading being a really cool thing</p>



<a name="126230681"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230681" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230681">(May 07 2018 at 19:57)</a>:</h4>
<p>but I also think it's clearly just harder to find your way around in</p>



<a name="126230736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230736">(May 07 2018 at 19:58)</a>:</h4>
<p>anyway I'm about to board a plane</p>



<a name="126230769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230769">(May 07 2018 at 19:59)</a>:</h4>
<p>the larger picture is: I think we're in an experimentation phase, but it'd be nice to find a single "Chat tech" that can serve rust-lang well as our "official home" -- IRC is not it -- gitter wasn't really it -- I thought  it'd be nice to try experimenting with Zulip and Discord. Anyway, it's still experimentation phase, so I'm happy to also hang out here a little longer.</p>



<a name="126230809"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230809" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230809">(May 07 2018 at 20:00)</a>:</h4>
<p>but I also feel like Discord is a overall a slicker candidate</p>



<a name="126230830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230830">(May 07 2018 at 20:00)</a>:</h4>
<p>they're missing one or two features I want but it did sound like they would add them ;)</p>



<a name="126230834"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230834" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230834">(May 07 2018 at 20:00)</a>:</h4>
<p>(notably linking to msgs is not yet easy)</p>



<a name="126230837"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230837" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230837">(May 07 2018 at 20:00)</a>:</h4>
<p>plus they use Rust, always a plus for me :P</p>



<a name="126230839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230839">(May 07 2018 at 20:00)</a>:</h4>
<p>anyway, I've got to run to grab a plane</p>



<a name="126230850"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126230850" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126230850">(May 07 2018 at 20:01)</a>:</h4>
<p>safe travels!</p>



<a name="126270042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270042">(May 08 2018 at 15:43)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> you around? (Also, are we using this or Discord? =)</p>



<a name="126270048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270048">(May 08 2018 at 15:43)</a>:</h4>
<p>I see some people on Discord but not all</p>



<a name="126270131"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270131" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270131">(May 08 2018 at 15:44)</a>:</h4>
<p><span class="user-mention" data-user-id="116110">@Chris Vittal</span> I saw your changes to the borrow-check <code>relation</code> branch -- I was thining about trying to connect that to the main algorithm</p>



<a name="126270532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270532">(May 08 2018 at 15:53)</a>:</h4>
<p>We probably should use this tonight</p>



<a name="126270576"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270576" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270576">(May 08 2018 at 15:54)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> (I’m not really around as I need my hands free atm)</p>



<a name="126270586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126270586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126270586">(May 08 2018 at 15:54)</a>:</h4>
<p>that's fine. I'll try to leave some notes, I may or may not make the mtg</p>



<a name="126276456"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126276456" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126276456">(May 08 2018 at 18:16)</a>:</h4>
<p>I won't be able to make the meeting today, have to take a final exam. I wrote up and pasted some pictures of a visualization I was playing with. I'm not sure if it's useful but making it was fun ;)</p>



<a name="126278546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126278546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126278546">(May 08 2018 at 19:08)</a>:</h4>
<p>hmm, so who <em>is</em> going to be able to make the meeting today? Maybe its too late to say this, but should we just consider rescheduling to later this week?</p>



<a name="126278549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126278549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126278549">(May 08 2018 at 19:08)</a>:</h4>
<p>(I'll ask again in 22 minutes when the meeting is supposed to start.)</p>



<a name="126278666"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126278666" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126278666">(May 08 2018 at 19:11)</a>:</h4>
<p>I can make it but it's the same "just keeping in the loop, back next week" response as every week.</p>



<a name="126278798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126278798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126278798">(May 08 2018 at 19:14)</a>:</h4>
<p>I should also be able to join. However, I do not have anything new to report because I am still trying to figure out how to encode my experiment in timely. (I want to check if it would be enough to kill subsets only on loop back edges.)</p>



<a name="126279523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126279523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126279523">(May 08 2018 at 19:33)</a>:</h4>
<p>I left some notes in the paper</p>



<a name="126290599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126290599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126290599">(May 08 2018 at 23:59)</a>:</h4>
<p><span class="user-mention" data-user-id="116106">@Reed Koser</span> looking at your graph from the paper, I see a lot of black :) are there lots of regions with no relations at all? or is it just that a single pixel doesn't show up?</p>



<a name="126291272"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126291272" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126291272">(May 09 2018 at 00:17)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> in the first picture there's lots of empty space because the regions are very sparse, in the second picture it's because they're plotted as a scattergram and not a proper matrix plot</p>



<a name="126291323"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126291323" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126291323">(May 09 2018 at 00:18)</a>:</h4>
<p><a href="https://gist.github.com/bobtwinkles/c7c0342046dec2dd0efced078ffa5797" target="_blank" title="https://gist.github.com/bobtwinkles/c7c0342046dec2dd0efced078ffa5797">source code of the analysis</a><br>
you'll need to install</p>



<a name="126291329"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126291329" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126291329">(May 09 2018 at 00:18)</a>:</h4>
<p><code>pyqtgraph</code> and one of the flavors of python-qt bindings (pyqt-4, pyqt-5, there's a few others that work I think)</p>



<a name="126294761"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294761" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294761">(May 09 2018 at 02:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116110">@Chris Vittal</span> I was messing about with integrating the <code>EdgeRelation</code> into the borrow-check -- I may push a WIP WIP commit -- one operation that seems to be missing is the "iterate over all edges", we can't really do that efficienctly =) (but we could thread another linked list to do that)</p>



<a name="126294762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294762">(May 09 2018 at 02:14)</a>:</h4>
<p>for now I will iterate over all edges starting from each live region</p>



<a name="126294813"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294813" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294813">(May 09 2018 at 02:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> do you still want that integration with the <code>histo</code> crate or <span class="user-mention" data-user-id="116106">@Reed Koser</span> work supersedes it?</p>



<a name="126294941"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294941" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294941">(May 09 2018 at 02:20)</a>:</h4>
<p><span class="user-mention" data-user-id="116013">@qmx</span> still seems useful to me, particularly if we can feed it different sorts of tuples.</p>



<a name="126294946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294946">(May 09 2018 at 02:21)</a>:</h4>
<p>good, I'll keep poking at it then - wasn't sure when I've seen the issue closed</p>



<a name="126294947"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294947" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294947">(May 09 2018 at 02:21)</a>:</h4>
<p>(I didn't notice it was closd)</p>



<a name="126294949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294949">(May 09 2018 at 02:21)</a>:</h4>
<p>I know that I am personally much more likely to dump data in a text-based way :P just because I'm lazy to install everything</p>



<a name="126294950"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294950" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294950">(May 09 2018 at 02:21)</a>:</h4>
<p>probably github being <em>too</em> smart about stuff :P</p>



<a name="126294952"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294952" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294952">(May 09 2018 at 02:21)</a>:</h4>
<p>#teamlazy</p>



<a name="126294996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126294996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126294996">(May 09 2018 at 02:22)</a>:</h4>
<p>that does happen</p>



<a name="126297380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126297380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126297380">(May 09 2018 at 03:47)</a>:</h4>
<p>yeah, my work doesn't intersect much with the <code>histo</code> stuff @qmx. My "tool" is a python script because I knew that would be easier than trying to get interactive plotting in Rust =)</p>



<a name="126298916"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126298916" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Chris Vittal <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126298916">(May 09 2018 at 04:43)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> , that's fine. I'll be happy to take a look.</p>



<a name="126310402"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126310402" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126310402">(May 09 2018 at 11:31)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> on Gitter, you wrote this example:</p>
<div class="codehilite"><pre><span></span><span class="c1">//#![feature(nll)]</span>

<span class="k">struct</span> <span class="nc">A</span><span class="p">;</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">c</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Box</span>::<span class="n">new</span><span class="p">((</span><span class="n">A</span><span class="p">,</span><span class="w"> </span><span class="n">A</span><span class="p">));</span><span class="w"></span>

<span class="w">    </span><span class="c1">// Consume internals</span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">_a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">c</span><span class="p">.</span><span class="mi">0</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">_b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">c</span><span class="p">.</span><span class="mi">1</span><span class="p">;</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<p>I think that the reason this works with NLL borrow checker is that we started special-casing <code>Box</code> again. On the AST-based borrow checker, we had some steps to treat <code>Box</code> conservatively and hence once you moved out of <em>one</em> part, e.g. the field <code>0</code>, you would be considered to have moved the entire box. However those special cases were inconsistent and kind of hacky and we removed them in the MIR-based borrow checker, for better or worse.</p>
<p>cc <span class="user-mention" data-user-id="116083">@pnkfelix</span> this is something I've always wanted to revisit and make sure we are happy with =)</p>



<a name="126310870"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126310870" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126310870">(May 09 2018 at 11:46)</a>:</h4>
<p>We should probably open a bug specifically about revisiting that choice. (...... and maybe... shudder... an RFC..?)</p>



<a name="126311177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126311177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126311177">(May 09 2018 at 11:56)</a>:</h4>
<p>still thinking about the transitive closure mentioned in the borrowck repo, issue #6: completely commenting it out brings clap down from 147s to 9s (and of course misses half the tuples). Do we have an idea if those 9s are good, good enough, bad ?</p>



<a name="126311305"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126311305" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126311305">(May 09 2018 at 12:00)</a>:</h4>
<p>it's obviously a lot better =) that's a good measurement, though. Still not great. It'd be good to start investigating where <em>that</em> time is going as well (for once we solve the TC problem)</p>



<a name="126311559"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126311559" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126311559">(May 09 2018 at 12:08)</a>:</h4>
<p>I wonder if frank mcsherry has debugging and profiling tools for timely :)</p>



<a name="126312365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312365">(May 09 2018 at 12:30)</a>:</h4>
<p>not sure, he mentioned to me at one point that a useful thing was just to stick some calls to <code>count</code> to get a view of raw number of tuples flowing about at any point</p>



<a name="126312534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312534">(May 09 2018 at 12:35)</a>:</h4>
<p>(I had forgotten to check this data point as comparison, but the regular NLL analysis takes 16s on this machine)</p>



<a name="126312587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312587">(May 09 2018 at 12:36)</a>:</h4>
<p>9s still feels like a tremendous amount to me</p>



<a name="126312595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312595">(May 09 2018 at 12:37)</a>:</h4>
<p>I think that part of the problem is that we are propagating things "per point" right now</p>



<a name="126312598"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312598" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312598">(May 09 2018 at 12:37)</a>:</h4>
<p>and there are 2x points per MIR <em>statement</em> (not even basic blocks)</p>



<a name="126312655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312655">(May 09 2018 at 12:39)</a>:</h4>
<p>to me too unfortunately (btw the other subset rules apart from the TC didn't seem to be heavy, making subset = outlives didn't change those 9s)</p>



<a name="126312662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312662">(May 09 2018 at 12:40)</a>:</h4>
<p>having the invalidation points will be interesting to see as well</p>



<a name="126312849"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126312849" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126312849">(May 09 2018 at 12:44)</a>:</h4>
<p>it would also be interesting to see what kind of query plans would a graph database generate for these relations :)</p>



<a name="126315371"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126315371" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126315371">(May 09 2018 at 13:47)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> <span class="user-mention" data-user-id="116013">@qmx</span> now we can't talk anymore :)</p>



<a name="126315410"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126315410" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126315410">(May 09 2018 at 13:48)</a>:</h4>
<p>heh</p>



<a name="126315416"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126315416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126315416">(May 09 2018 at 13:48)</a>:</h4>
<p>I wonder if zulip also supports "heading" tags</p>



<a name="126315418"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126315418" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126315418">(May 09 2018 at 13:48)</a>:</h4>
<p>## Foo</p>



<a name="126315420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126315420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126315420">(May 09 2018 at 13:48)</a>:</h4>
<p>good, that's a kind of misfeature :)</p>



<a name="126323388"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126323388" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126323388">(May 09 2018 at 16:52)</a>:</h4>
<blockquote>
<p>we started special-casing <code>Box</code> again. [...]  we removed [those special cases] in the MIR-based borrow checker</p>
</blockquote>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> so, is it special-cased before, after, or differently with MIR borrowck?</p>



<a name="126323406"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126323406" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126323406">(May 09 2018 at 16:53)</a>:</h4>
<p>And here's a contentious question: is the name "non-lexical lifetimes" a misnomer? (not as bad as OIBIT, though)</p>



<a name="126323421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126323421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126323421">(May 09 2018 at 16:53)</a>:</h4>
<p>because <em>lifetimes</em> don't really change with NLL; it's just the length of a borrow that changes</p>



<a name="126323604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126323604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126323604">(May 09 2018 at 16:58)</a>:</h4>
<p>whatever the new name is, it has to have "loans" on it <span class="emoji emoji-1f602" title="joy">:joy:</span></p>



<a name="126324045"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324045" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324045">(May 09 2018 at 17:08)</a>:</h4>
<p>I mean, the name doesn't really have to change, as <span class="user-mention" data-user-id="116009">@nikomatsakis</span> points out, once it's enabled, no one will ever think about it again.<br>
It will "just be"</p>



<a name="126324157"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324157" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324157">(May 09 2018 at 17:11)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> I would say it is special-cased differently :)</p>



<a name="126324201"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324201" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324201">(May 09 2018 at 17:12)</a>:</h4>
<p>but the old borrow checker was aiming <strong>not</strong> to special-case it -- meaning, to only permit you to do things you could emulate with a <code>fn into_inner(self)</code> etc</p>



<a name="126324212"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324212" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324212">(May 09 2018 at 17:12)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> and another missing piece of the puzzle for me: where does the <em>borrow</em> checker come into play with this at all? I'd understand if there were some references involved...</p>



<a name="126324218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324218">(May 09 2018 at 17:13)</a>:</h4>
<p>the borrow checker checks moves too</p>



<a name="126324225"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324225" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324225">(May 09 2018 at 17:13)</a>:</h4>
<p>they interact</p>



<a name="126324233"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324233" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324233">(May 09 2018 at 17:13)</a>:</h4>
<p>TIL. I guess <code>borrow_or_move_ck</code> isn't as smooth of a name</p>



<a name="126324237"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324237" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324237">(May 09 2018 at 17:13)</a>:</h4>
<p>"ownership-check"</p>



<a name="126324241"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324241" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324241">(May 09 2018 at 17:13)</a>:</h4>
<p>initially the borrow checker did <em>not</em> check moves</p>



<a name="126324242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324242">(May 09 2018 at 17:13)</a>:</h4>
<p>but that changed</p>



<a name="126324289"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324289" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324289">(May 09 2018 at 17:14)</a>:</h4>
<p>technically that's a "sub-phase", essentially, the "initialization check" (where a move is a "deinitialization")</p>



<a name="126324500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324500">(May 09 2018 at 17:18)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> any objections to me stating that "NLL" is poorly named in a stack overflow answer? <span class="emoji emoji-1f607" title="innocent">:innocent:</span></p>



<a name="126324513"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324513" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324513">(May 09 2018 at 17:19)</a>:</h4>
<p>I don't disagree</p>



<a name="126324523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324523">(May 09 2018 at 17:19)</a>:</h4>
<p>so "no" I suppose</p>



<a name="126324526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324526">(May 09 2018 at 17:19)</a>:</h4>
<p>I mean, I plan on having more words to back it up. And mentioning MIR borrowck as the core piece</p>



<a name="126324581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324581">(May 09 2018 at 17:20)</a>:</h4>
<p>"MIR ownership check" I suppose ;-)</p>



<a name="126324594"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324594" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324594">(May 09 2018 at 17:20)</a>:</h4>
<p>borrowck2.0</p>



<a name="126324597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126324597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126324597">(May 09 2018 at 17:20)</a>:</h4>
<p>"Now more precise!"</p>



<a name="126326051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126326051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126326051">(May 09 2018 at 17:53)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span>  Have you made any progress on <a href="https://github.com/rust-lang-nursery/borrow-check/issues/4" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/issues/4">https://github.com/rust-lang-nursery/borrow-check/issues/4</a> ? I'd really like to have that information and have time to hack it up today =)</p>



<a name="126326210"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126326210" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126326210">(May 09 2018 at 17:57)</a>:</h4>
<p>(though for general reference, my schedule is changing a lot starting next week and I won't be able to make the weekly meetings unless they get moved sometime that's not from ~9am to 6pm PDT/12pm to 9pm EDT)</p>



<a name="126326279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126326279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126326279">(May 09 2018 at 17:58)</a>:</h4>
<p>I should still be able to stay in touch async though</p>



<a name="126326291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126326291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126326291">(May 09 2018 at 17:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116106">@Reed Koser</span> I don't think <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> has had a chance to do anything. If you have time to hack on it, I say go for it!</p>



<a name="126327200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327200">(May 09 2018 at 18:19)</a>:</h4>
<p>it seems the datalog compiled to a binary with soufflé is slower than the timely analysis ? (the counts seem to match, but I'll need to check the output :) -- I killed the single threaded soufflé since it was so long, but at 8 threads it took 92s.</p>



<a name="126327390"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327390" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327390">(May 09 2018 at 18:23)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> note that the datalog can be optimized by reordering clauses sometimes</p>



<a name="126327393"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327393" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327393">(May 09 2018 at 18:23)</a>:</h4>
<p>I didn't make any effort to order it intelligently</p>



<a name="126327394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327394">(May 09 2018 at 18:24)</a>:</h4>
<p>that said, I think that differential-dataflow is quite competitive</p>



<a name="126327446"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327446" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327446">(May 09 2018 at 18:24)</a>:</h4>
<p>but I found massive (like 10x) differences in souffle's performance by doing some reordering</p>



<a name="126327449"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327449" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327449">(May 09 2018 at 18:24)</a>:</h4>
<p>in prior experiments</p>



<a name="126327479"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327479" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327479">(May 09 2018 at 18:25)</a>:</h4>
<p>you have to sort of visualize how many tuples will result...</p>



<a name="126327483"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126327483" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126327483">(May 09 2018 at 18:25)</a>:</h4>
<p>basically prefer this that will "Kill of" stuff</p>



<a name="126328106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126328106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126328106">(May 09 2018 at 18:40)</a>:</h4>
<p>indeed reordering and using their profiler could be an interesting experiment, I was mostly trying it out in case it was faster out of the box, and could have offered insights on the timely plan, but alas</p>



<a name="126328159"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126328159" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126328159">(May 09 2018 at 18:41)</a>:</h4>
<blockquote>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span>  Have you made any progress on <a href="https://github.com/rust-lang-nursery/borrow-check/issues/4" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/issues/4">https://github.com/rust-lang-nursery/borrow-check/issues/4</a> ? I'd really like to have that information and have time to hack it up today =)</p>
</blockquote>
<p>I haven't started yet ... is the next task I have on my todo list</p>



<a name="126328169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126328169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126328169">(May 09 2018 at 18:41)</a>:</h4>
<p>probably starting today or tomorrow</p>



<a name="126328419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126328419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126328419">(May 09 2018 at 18:46)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> not sure if <span class="user-mention" data-user-id="116106">@Reed Koser</span> will wind up hacking on that, but there was another "bespoke" data structure I wanted to play around with, I could try to write out the details</p>



<a name="126328426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126328426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126328426">(May 09 2018 at 18:47)</a>:</h4>
<p>though I should work more on that "harness"</p>



<a name="126331215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126331215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126331215">(May 09 2018 at 19:53)</a>:</h4>
<p><span class="user-mention" data-user-id="116106">@Reed Koser</span> are you hacking on #4 after all?</p>



<a name="126331275"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126331275" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126331275">(May 09 2018 at 19:54)</a>:</h4>
<p>slowly, yes</p>



<a name="126361673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361673">(May 10 2018 at 12:03)</a>:</h4>
<p>grr what the heck is going on -- so I merged <a href="https://github.com/rust-lang-nursery/borrow-check/pull/18" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/pull/18">https://github.com/rust-lang-nursery/borrow-check/pull/18</a> -- but now, on my mac anyway, I am not able to build anymore</p>



<a name="126361676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361676">(May 10 2018 at 12:03)</a>:</h4>
<p>can someone else test?</p>



<a name="126361682"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361682">(May 10 2018 at 12:03)</a>:</h4>
<p>can do</p>



<a name="126361729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361729">(May 10 2018 at 12:04)</a>:</h4>
<p>(you will need a recent nightly)</p>



<a name="126361739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361739">(May 10 2018 at 12:05)</a>:</h4>
<p>is 3 days ago recent enough?</p>



<a name="126361740"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361740" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361740">(May 10 2018 at 12:05)</a>:</h4>
<p>it's weird though because travis is green...</p>



<a name="126361742"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361742" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361742">(May 10 2018 at 12:05)</a>:</h4>
<p>should be, yeah</p>



<a name="126361788"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361788" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361788">(May 10 2018 at 12:06)</a>:</h4>
<p>yep, master compiled just fine</p>



<a name="126361794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361794">(May 10 2018 at 12:06)</a>:</h4>
<p>huh. strange.</p>



<a name="126361816"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361816" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361816">(May 10 2018 at 12:07)</a>:</h4>
<p><span class="user-mention" data-user-id="116013">@qmx</span> which nightly are you using? I am using:</p>
<div class="codehilite"><pre><span></span>&gt; cargo +nightly --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>9e53ac6e6 <span class="m">2018</span>-05-07<span class="o">)</span>
</pre></div>



<a name="126361862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361862">(May 10 2018 at 12:08)</a>:</h4>
<p><code>rustc 1.27.0-nightly (91db9dcf3 2018-05-04)</code></p>



<a name="126361865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361865">(May 10 2018 at 12:08)</a>:</h4>
<p>updating my nightly to see if something broke</p>



<a name="126361866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361866">(May 10 2018 at 12:08)</a>:</h4>
<p>I will try that one</p>



<a name="126361869"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361869" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361869">(May 10 2018 at 12:08)</a>:</h4>
<p>/me thinks he will regret that</p>



<a name="126361875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361875">(May 10 2018 at 12:09)</a>:</h4>
<p>the conference wifi is not too fast though</p>



<a name="126361878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361878">(May 10 2018 at 12:09)</a>:</h4>
<p>so my ability to download new nightly's is limited :P</p>



<a name="126361885"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126361885" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126361885">(May 10 2018 at 12:09)</a>:</h4>
<p>been there</p>



<a name="126362023"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362023" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362023">(May 10 2018 at 12:13)</a>:</h4>
<p>argh, this is the bane of my existance </p>
<div class="codehilite"><pre><span></span>error: could not rename component directory from &#39;/home/qmx/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/codegen-backends&#39; to &#39;/home/qmx/.rustup/tmp/gpz2qvd0u6nl969o_dir/bk&#39;
info: caused by: Invalid cross-device link (os error 18)
</pre></div>


<p>I hit this every single time</p>



<a name="126362026"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362026" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362026">(May 10 2018 at 12:13)</a>:</h4>
<p>what the</p>



<a name="126362027"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362027" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362027">(May 10 2018 at 12:13)</a>:</h4>
<p>I've never heard of that</p>



<a name="126362070"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362070" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362070">(May 10 2018 at 12:14)</a>:</h4>
<p>ok, I managed to download 2018-05-04, building now</p>



<a name="126362073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362073">(May 10 2018 at 12:14)</a>:</h4>
<p>I don't even know where to start debugging this</p>



<a name="126362087"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362087" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362087">(May 10 2018 at 12:15)</a>:</h4>
<p>hmm 2018-05-04 seems to be working. I wonder if something happened to break it</p>



<a name="126362144"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362144" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362144">(May 10 2018 at 12:17)</a>:</h4>
<p>I can confirm that master fails to compile with <code>cargo 1.27.0-nightly (9e53ac6e6 2018-05-07)</code>.</p>



<a name="126362149"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362149" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362149">(May 10 2018 at 12:17)</a>:</h4>
<p>there's something that's annoying me with <code>rustc</code> lately - near the end of the build process CPU usage drops to zero, idles 10s, then spikes and finishes the build</p>



<a name="126362203"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362203" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362203">(May 10 2018 at 12:19)</a>:</h4>
<p>overall the wall clock time feels longer</p>



<a name="126362218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362218">(May 10 2018 at 12:19)</a>:</h4>
<p>curious</p>



<a name="126362347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362347">(May 10 2018 at 12:23)</a>:</h4>
<p><code>cargo +nightly-2018-05-06 build --release</code> successfully compiled.</p>



<a name="126362405"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362405" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362405">(May 10 2018 at 12:24)</a>:</h4>
<p>strange. for me, it does not.</p>



<a name="126362406"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362406" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362406">(May 10 2018 at 12:24)</a>:</h4>
<p>but 2018-05-04 does</p>



<a name="126362407"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362407" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362407">(May 10 2018 at 12:24)</a>:</h4>
<p>I wonder if something else is weird on my system</p>



<a name="126362493"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362493" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362493">(May 10 2018 at 12:26)</a>:</h4>
<p>I am confused:</p>
<div class="codehilite"><pre><span></span>$ cargo +nightly-2018-05-06 --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>af3f1cd29 <span class="m">2018</span>-05-03<span class="o">)</span>
</pre></div>


<p>Shouldn't it be <code>2018-05-06</code>, or at least <code>2018-05-05</code>?</p>



<a name="126362505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362505">(May 10 2018 at 12:26)</a>:</h4>
<p>that...is confusing</p>



<a name="126362715"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362715" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362715">(May 10 2018 at 12:32)</a>:</h4>
<div class="codehilite"><pre><span></span>$ cargo +nightly-2018-05-06 --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>af3f1cd29 <span class="m">2018</span>-05-03<span class="o">)</span>

$ cargo +nightly-2018-05-07 --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>af3f1cd29 <span class="m">2018</span>-05-03<span class="o">)</span>

$ cargo +nightly-2018-05-08 --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>af3f1cd29 <span class="m">2018</span>-05-03<span class="o">)</span>

$ cargo +nightly-2018-05-09 --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>af3f1cd29 <span class="m">2018</span>-05-03<span class="o">)</span>

$ cargo +nightly --version
cargo <span class="m">1</span>.27.0-nightly <span class="o">(</span>9e53ac6e6 <span class="m">2018</span>-05-07<span class="o">)</span>
</pre></div>



<a name="126362726"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362726" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362726">(May 10 2018 at 12:33)</a>:</h4>
<p>I'll try to reinstall rustup.</p>



<a name="126362735"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362735" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362735">(May 10 2018 at 12:33)</a>:</h4>
<p>sometimes all the nightly components don't successfully build, could be related to that</p>



<a name="126362851"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362851" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362851">(May 10 2018 at 12:36)</a>:</h4>
<p>If this is a case, then when was the latest nightly build?</p>



<a name="126362866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126362866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126362866">(May 10 2018 at 12:37)</a>:</h4>
<p>In other words, why <code>cargo +nightly --version</code> reports <code>2018-05-07</code>, but <code>cargo +nightly-2018-05-09 --version</code> reports <code>2018-05-03</code>?</p>



<a name="126363171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126363171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126363171">(May 10 2018 at 12:46)</a>:</h4>
<p>Ok, I think I finally understood. The reported date is the commit date while the date in the <code>+nightly-2018-05-09</code> is the build date, which can be several days later.</p>



<a name="126363354"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126363354" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126363354">(May 10 2018 at 12:52)</a>:</h4>
<p>Anyway, <code>cargo +nightly-2018-05-07 build --release</code> is the latest version that still works for me.</p>



<a name="126363378"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126363378" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126363378">(May 10 2018 at 12:53)</a>:</h4>
<p>So, most likely something happened between the rustc commits <code>428ea5f6b 2018-05-06</code> and <code>565235ee7 2018-05-07</code>.</p>



<a name="126363499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126363499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126363499">(May 10 2018 at 12:57)</a>:</h4>
<p>thanks <span class="user-mention" data-user-id="116109">@Vytautas Astrauskas</span>! I should file a bug....</p>



<a name="126363553"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126363553" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126363553">(May 10 2018 at 12:58)</a>:</h4>
<p>No problem. <span class="emoji emoji-263a" title="relaxed">:relaxed:</span></p>



<a name="126379628"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126379628" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126379628">(May 10 2018 at 19:10)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> off-the-wall question, but the <code>Box</code> special casing we were talking about doesn't help <code>Box&lt;FnOnce&gt;</code>, does it?</p>



<a name="126379758"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126379758" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126379758">(May 10 2018 at 19:13)</a>:</h4>
<p>no</p>



<a name="126381138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126381138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126381138">(May 10 2018 at 19:42)</a>:</h4>
<p>booo</p>



<a name="126381148"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126381148" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126381148">(May 10 2018 at 19:42)</a>:</h4>
<p>I really want a good-natured "boo" reaction emoji</p>



<a name="126388540"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388540" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388540">(May 10 2018 at 22:51)</a>:</h4>
<p>I opened two new issues on the borrow-checker repo with ideas for ways to make the input smaller:</p>
<ul>
<li><a href="https://github.com/rust-lang-nursery/borrow-check/issues/20" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/issues/20">https://github.com/rust-lang-nursery/borrow-check/issues/20</a></li>
<li><a href="https://github.com/rust-lang-nursery/borrow-check/issues/19" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/issues/19">https://github.com/rust-lang-nursery/borrow-check/issues/19</a></li>
</ul>



<a name="126388578"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388578" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388578">(May 10 2018 at 22:52)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> would the hypothetical datalog to DD builder emit semijoins when the previous predicate's output covers the next, and joins otherwise ?</p>



<a name="126388589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388589">(May 10 2018 at 22:52)</a>:</h4>
<p>by "covers" you mean all variables that appear in the second predicate also appeared in the first?</p>



<a name="126388593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388593">(May 10 2018 at 22:52)</a>:</h4>
<p>if so, yes</p>



<a name="126388595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388595">(May 10 2018 at 22:52)</a>:</h4>
<p>yeah</p>



<a name="126388599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388599">(May 10 2018 at 22:53)</a>:</h4>
<p>I think the idea would roughly be:</p>
<ul>
<li>group variables into three groups (only pred1, both preds, only pred2)</li>
<li>map first pred to contain <code>(BothPreds, OnlyPred1)</code> </li>
<li>if OnlyPred2 is not empty:<ul>
<li>map second pred to contain <code>(BothPreds, OnlyPred2)</code></li>
<li>join those two mapped things</li>
</ul>
</li>
<li>else:<ul>
<li>map second pred to contain <code>BothPreds</code></li>
<li>semijoin</li>
</ul>
</li>
</ul>
<p>(ignoring negative things)</p>



<a name="126388654"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388654" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388654">(May 10 2018 at 22:54)</a>:</h4>
<p>probably some details wrong there</p>



<a name="126388659"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388659" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388659">(May 10 2018 at 22:54)</a>:</h4>
<p>so I feel the only grey area is when to use <code>iterate</code> vs other operators, or if there might need to be other inner timely scopes, etc</p>



<a name="126388663"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388663" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388663">(May 10 2018 at 22:55)</a>:</h4>
<p>ah, yes, recursion is a bit tricky</p>



<a name="126388668"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388668" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388668">(May 10 2018 at 22:55)</a>:</h4>
<p>there is a lower-level primitive you can use</p>



<a name="126388674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388674">(May 10 2018 at 22:55)</a>:</h4>
<p>but it would probably be good to build a DAG between relations</p>



<a name="126388678"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388678" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388678">(May 10 2018 at 22:55)</a>:</h4>
<p>you could even not support complex cycles to begin with</p>



<a name="126388679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388679">(May 10 2018 at 22:55)</a>:</h4>
<p>most of the time the relations just recurse on themselves anyway</p>



<a name="126388725"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388725" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388725">(May 10 2018 at 22:56)</a>:</h4>
<p>or maybe have a slightly "richer" input format, to manually control such cases</p>



<a name="126388782"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388782" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388782">(May 10 2018 at 22:58)</a>:</h4>
<p>right, it doesn't have to <em>really</em> be datalog etc</p>



<a name="126388786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388786">(May 10 2018 at 22:58)</a>:</h4>
<p>especially not to start :)</p>



<a name="126388799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388799">(May 10 2018 at 22:59)</a>:</h4>
<p>eg <code>.decl requires(R, B, P) iterates borrow_region</code></p>



<a name="126388808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126388808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126388808">(May 10 2018 at 22:59)</a>:</h4>
<p>thanks for the answers, this seems like it would be fun to do :p</p>



<a name="126389886"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126389886" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126389886">(May 10 2018 at 23:31)</a>:</h4>
<p>I guess to work around the breakage we can revert <a href="https://github.com/rust-lang-nursery/borrow-check/pull/18" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/pull/18">https://github.com/rust-lang-nursery/borrow-check/pull/18</a> for now</p>



<a name="126389984"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126389984" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126389984">(May 10 2018 at 23:34)</a>:</h4>
<p><a href="https://github.com/rust-lang-nursery/borrow-check/pull/22" target="_blank" title="https://github.com/rust-lang-nursery/borrow-check/pull/22">https://github.com/rust-lang-nursery/borrow-check/pull/22</a></p>



<a name="126390195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390195">(May 10 2018 at 23:40)</a>:</h4>
<p>yea, that fixed it</p>



<a name="126390347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390347">(May 10 2018 at 23:44)</a>:</h4>
<p>I restarted travis on your PR <span class="user-mention" data-user-id="116013">@qmx</span></p>



<a name="126390463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390463">(May 10 2018 at 23:47)</a>:</h4>
<p>do we need to add <code>extern crate</code> again with the reverts?</p>



<a name="126390480"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390480" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390480">(May 10 2018 at 23:47)</a>:</h4>
<p>yes</p>



<a name="126390485"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390485" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390485">(May 10 2018 at 23:47)</a>:</h4>
<p>ah so your PR may need to be edited</p>



<a name="126390534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390534">(May 10 2018 at 23:48)</a>:</h4>
<p>ok, fixing</p>



<a name="126390539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390539">(May 10 2018 at 23:48)</a>:</h4>
<p>it was so refreshing <strong>not</strong> having to do that :P</p>



<a name="126390700"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390700" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390700">(May 10 2018 at 23:53)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> is your emacs rust syntax highlighting working with the nightly features or you just live with the breakage?</p>



<a name="126390741"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390741" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390741">(May 10 2018 at 23:54)</a>:</h4>
<p>it works for the most part? I haven't noticed any glaring problems</p>



<a name="126390754"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390754" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390754">(May 10 2018 at 23:55)</a>:</h4>
<p>yay, green PR</p>



<a name="126390815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390815">(May 10 2018 at 23:57)</a>:</h4>
<p>grr I feel like I'm constantly re-inventing things like <code>IndexVec</code></p>



<a name="126390818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390818">(May 10 2018 at 23:57)</a>:</h4>
<p>it'd be nice to pull that into a rust-lang-nursery crate</p>



<a name="126390864"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390864" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390864">(May 10 2018 at 23:58)</a>:</h4>
<p>sounds like boring janitorial work, how one can approach that?</p>



<a name="126390986"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390986" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390986">(May 11 2018 at 00:02)</a>:</h4>
<p>I wonder if we should just pull the entire <code>rustc_data_structures</code> crate, or break it up into smaller crates</p>



<a name="126390988"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126390988" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126390988">(May 11 2018 at 00:02)</a>:</h4>
<p>in any case, I can make some repos...</p>



<a name="126394348"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126394348" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126394348">(May 11 2018 at 02:02)</a>:</h4>
<p>I'm loving zulip threads. Made digesting a 99+ message backlog actually tractable <span class="emoji emoji-1f60d" title="heart eyes">:heart_eyes:</span></p>



<a name="126400305"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126400305" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126400305">(May 11 2018 at 05:45)</a>:</h4>
<p>yeah, i'm totally just clicking on the topics/threads rn to read the context, instead of going into the #wg-nll stream to read everything there</p>



<a name="126406868"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126406868" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126406868">(May 11 2018 at 09:34)</a>:</h4>
<blockquote>
<p>(though for general reference, my schedule is changing a lot starting next week and I won't be able to make the weekly meetings unless they get moved sometime that's not from ~9am to 6pm PDT/12pm to 9pm EDT)</p>
</blockquote>
<p>Maybe we should set up another doodle?</p>



<a name="126408672"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126408672" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126408672">(May 11 2018 at 10:34)</a>:</h4>
<blockquote>
<p>I'm loving zulip threads. Made digesting a 99+ message backlog actually tractable <span class="emoji emoji-1f60d" title="heart eyes">:heart_eyes:</span></p>
</blockquote>
<p>but you put this in the wrong thread! ;)</p>



<a name="126408928"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126408928" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126408928">(May 11 2018 at 10:42)</a>:</h4>
<p>(to clarify, I was thinking of the "gitter is dead" thread)</p>
<p>But actually it's pretty interesting that the threads help to catch up later. I can imagine that.</p>



<a name="126415804"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126415804" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126415804">(May 11 2018 at 13:53)</a>:</h4>
<p>agree with threads and catching up - can ignore what is uninteresting. needs to be sorted correctly tho</p>



<a name="126443180"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126443180" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126443180">(May 12 2018 at 01:33)</a>:</h4>
<blockquote>
<p>Mr-Darcy.</p>
</blockquote>



<a name="126483872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126483872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126483872">(May 13 2018 at 03:48)</a>:</h4>
<blockquote>
<p>argh, this is the bane of my existance </p>
</blockquote>
<p>error: could not rename component directory from '/home/qmx/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/codegen-backends' to '/home/qmx/.rustup/tmp/gpz2qvd0u6nl969o_dir/bk'<br>
info: caused by: Invalid cross-device link (os error 18)</p>
<div class="codehilite"><pre><span></span>I hit this every single time
</pre></div>


<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> so this error is this one <a href="https://github.com/rust-lang-nursery/rustup.rs/issues/1239" target="_blank" title="https://github.com/rust-lang-nursery/rustup.rs/issues/1239">https://github.com/rust-lang-nursery/rustup.rs/issues/1239</a> - quite a fun one to hit :)</p>



<a name="126495121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126495121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126495121">(May 13 2018 at 11:31)</a>:</h4>
<p>Argh</p>



<a name="126495123"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126495123" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126495123">(May 13 2018 at 11:31)</a>:</h4>
<p>Well at least you found the issue I guess</p>



<a name="126592595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126592595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126592595">(May 15 2018 at 13:55)</a>:</h4>
<p>One again I won't be able to make the triage meeting this week. I'll try to write up my progress quickly in the doc though</p>



<a name="126603670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126603670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126603670">(May 15 2018 at 18:01)</a>:</h4>
<p>can't make it today as well, i've got meetings all over</p>



<a name="126692680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126692680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126692680">(May 17 2018 at 11:16)</a>:</h4>
<p>is anyone else observing <code>borrow_check</code> rebuilding itself on every <code>cargo run</code>/<code>cargo test</code> invocation, starting from... well, I'm not getting consistent results as to which crate it starts from ...</p>



<a name="126693674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126693674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126693674">(May 17 2018 at 11:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> not for me on <code>cargo run</code> (but I'm on a rev a couple days old)</p>



<a name="126694953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126694953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126694953">(May 17 2018 at 12:24)</a>:</h4>
<p>I've noticed that in general (that cargo run likes to rebuild the root crate when I don't feel it should) but not for borrow check in particular</p>



<a name="126704814"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126704814" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126704814">(May 17 2018 at 16:03)</a>:</h4>
<p>the Mentat talk at rustconf will probably be very interesting wrt datalog :)</p>



<a name="126705539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126705539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126705539">(May 17 2018 at 16:22)</a>:</h4>
<p>there should be a rustc-conf where the ones that know explain the compiler and it's ecosystem :)</p>



<a name="126705546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126705546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126705546">(May 17 2018 at 16:22)</a>:</h4>
<p>that would be super cool</p>



<a name="126729068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126729068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126729068">(May 18 2018 at 02:51)</a>:</h4>
<p>some days ago we were talking about rustc compile times</p>



<a name="126729072"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126729072" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126729072">(May 18 2018 at 02:51)</a>:</h4>
<p>I did the full thing, without build directory</p>



<a name="126729073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126729073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126729073">(May 18 2018 at 02:51)</a>:</h4>
<p>it took on my machine 145 minutes</p>



<a name="126729120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126729120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126729120">(May 18 2018 at 02:52)</a>:</h4>
<p>I was unplugged, unsure if my OS has something configured that could have slowed down or something</p>



<a name="126729121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126729121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126729121">(May 18 2018 at 02:53)</a>:</h4>
<p>will try again tomorrow to see this</p>



<a name="126748518"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126748518" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126748518">(May 18 2018 at 13:14)</a>:</h4>
<p>Has anything changed since I took a break that would cause bootstrap to fail with <code>lldb --version</code>? Happening on existing cloned repos when I pull and with new clones.</p>



<a name="126749905"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126749905" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126749905">(May 18 2018 at 13:37)</a>:</h4>
<div class="codehilite"><pre><span></span>thread &#39;main&#39; panicked at &#39;&quot;lldb&quot; &quot;--version&quot; failed Output { status: ExitStatus(ExitStatus(32512)), stdout: &quot;&quot;, stderr: &quot;&quot; }&#39;, bootstrap/sanity.rs:243:24
note: Run with `RUST_BACKTRACE=1` for a backtrace.
</pre></div>



<a name="126749978"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126749978" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126749978">(May 18 2018 at 13:38)</a>:</h4>
<p>uh...</p>



<a name="126749980"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126749980" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126749980">(May 18 2018 at 13:38)</a>:</h4>
<p>I have no idea :)</p>



<a name="126755968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126755968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126755968">(May 18 2018 at 15:47)</a>:</h4>
<p>I will have some time on my hands after work today/this weekend. I saw that there were a couple of AIs from the "more future plans" thread, what would be the most useful thing for me to work on from there?</p>



<a name="126755977"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126755977" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126755977">(May 18 2018 at 15:47)</a>:</h4>
<p>"AI"?</p>



<a name="126756020"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756020" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756020">(May 18 2018 at 15:48)</a>:</h4>
<p>Err, action item</p>



<a name="126756042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756042">(May 18 2018 at 15:48)</a>:</h4>
<p>Sorry, jargon has permeated my brain</p>



<a name="126756058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756058">(May 18 2018 at 15:48)</a>:</h4>
<p>ha</p>



<a name="126756067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756067">(May 18 2018 at 15:49)</a>:</h4>
<p>I agree there are some distinct action items</p>



<a name="126756071"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756071" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756071">(May 18 2018 at 15:49)</a>:</h4>
<p>I'm feeling a bit disorganized just now</p>



<a name="126756077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756077">(May 18 2018 at 15:49)</a>:</h4>
<p>I will try to write a kind of plan on an issue later today though</p>



<a name="126756163"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756163" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756163">(May 18 2018 at 15:51)</a>:</h4>
<p>Sounds good, I'm not free until 6 or 7 PDT anyway</p>



<a name="126756170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126756170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126756170">(May 18 2018 at 15:51)</a>:</h4>
<p>Just wanted to get the ball rolling a bit <span class="emoji emoji-1f60a" title="blush">:blush:</span></p>



<a name="126757714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126757714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126757714">(May 18 2018 at 16:25)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> Do you happen to know if there's a NLL test for "recursive mutable borrows"?</p>
<p>Specifically, this code fails pre-NLL and works post-NLL</p>
<div class="codehilite"><pre><span></span><span class="k">type</span> <span class="nc">Link</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Option</span><span class="o">&lt;</span><span class="nb">Box</span><span class="o">&lt;</span><span class="n">Node</span><span class="o">&gt;&gt;</span><span class="p">;</span><span class="w"></span>

<span class="k">struct</span> <span class="nc">Node</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">next</span>: <span class="nc">Link</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">struct</span> <span class="nc">Recursive</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">root</span>: <span class="nc">Link</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">impl</span><span class="w"> </span><span class="n">Recursive</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">fn</span> <span class="nf">back</span><span class="p">(</span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="bp">self</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="n">Link</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">anchor</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">root</span><span class="p">;</span><span class="w"></span>
<span class="w">        </span><span class="k">while</span><span class="w"> </span><span class="kd">let</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="k">ref</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">node</span><span class="p">)</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">*</span><span class="n">anchor</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="n">anchor</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="n">node</span><span class="p">.</span><span class="n">next</span><span class="p">;</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">        </span><span class="n">anchor</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<p>It's quite a popular Stack Overflow question, so I think it's worth pinning down with a test.</p>



<a name="126758954"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126758954" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126758954">(May 18 2018 at 16:57)</a>:</h4>
<p>I believe there is a test for that, yes, but I don't know the name off hand</p>



<a name="126761456"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126761456" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126761456">(May 18 2018 at 17:53)</a>:</h4>
<p>Just watching that video - very helpful! Code walkthroughs like that are something we should do more of.</p>



<a name="126761694"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126761694" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126761694">(May 18 2018 at 17:59)</a>:</h4>
<p>I want to start doing it more often. I should make a little YouTube channel or something. If you're interested in being a guinea pig, let me know :)</p>



<a name="126761752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126761752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126761752">(May 18 2018 at 18:00)</a>:</h4>
<p>I'd be up for being a guinea pig.</p>



<a name="126762314"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762314" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762314">(May 18 2018 at 18:15)</a>:</h4>
<p>gotta figure out what to walk through I suppose :)</p>



<a name="126762316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762316">(May 18 2018 at 18:15)</a>:</h4>
<p>we could try to look at that perf problem I was talking about earlier</p>



<a name="126762372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762372">(May 18 2018 at 18:16)</a>:</h4>
<p>Yeah, that would be good, I'm still not all that sure what specific thing I can be digging into.</p>



<a name="126762583"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762583" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762583">(May 18 2018 at 18:21)</a>:</h4>
<p>hmm — want to try that shortly?</p>



<a name="126762587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762587">(May 18 2018 at 18:21)</a>:</h4>
<p>like, in 30min to an hour or so?</p>



<a name="126762629"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762629" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762629">(May 18 2018 at 18:22)</a>:</h4>
<p>Yeah, sure.</p>



<a name="126762663"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762663" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762663">(May 18 2018 at 18:23)</a>:</h4>
<p>ok, maybe on the hour? (that is, 3pm my time — probably 8pm yours?) I actually could do it whenever I suppose</p>



<a name="126762703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762703">(May 18 2018 at 18:24)</a>:</h4>
<p>I'm free for the rest of the day, whenever suits you.</p>



<a name="126762709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762709">(May 18 2018 at 18:24)</a>:</h4>
<p>if it works for you, how about in 5 minutes? :)</p>



<a name="126762711"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762711" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762711">(May 18 2018 at 18:24)</a>:</h4>
<p>I'll just go find a room</p>



<a name="126762728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126762728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126762728">(May 18 2018 at 18:24)</a>:</h4>
<p>Sure.</p>



<a name="126836057"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126836057" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126836057">(May 20 2018 at 15:57)</a>:</h4>
<p>Should <span class="emoji emoji-1f438" title="frog">:frog:</span> have <code>#![feature(nll)]</code> enabled? I think so. Full Ouroboros.</p>



<a name="126836313"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126836313" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> qmx <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126836313">(May 20 2018 at 16:07)</a>:</h4>
<p>Do this means downstream datafrog users would not be able to compile it with stable?</p>



<a name="126869852"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869852" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869852">(May 21 2018 at 12:26)</a>:</h4>
<p>Hey <span class="user-mention" data-user-id="116009">@nikomatsakis</span> I just noticed: back in December ariel added the <code>fn before_statement_effect</code> and <code>fn before_terminator_effect</code> stuff. But as far as I can telll, a later PR by <span class="user-mention" data-user-id="116106">@Reed Koser</span>  recreated those same effects (which is to call <code>kill_loans_out_of_scope_at</code> at the start of <code>fn statement_effect</code> and <code>fn terminator_effect</code>.</p>



<a name="126869880"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869880" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869880">(May 21 2018 at 12:27)</a>:</h4>
<p>ah, interesting. Perhaps a sort of race condition.</p>



<a name="126869881"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869881" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869881">(May 21 2018 at 12:27)</a>:</h4>
<p>So that raises some questions. E.g. do we still need <code>fn before_foo_effect</code> in the dataflow API? And how much efficiency are we losing by having those extra calls to <code>kill_loans_out_of_scope_at</code>? Anyway I will investigate further. Its possible I've misunderstood something.</p>



<a name="126869882"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869882" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869882">(May 21 2018 at 12:27)</a>:</h4>
<p>Oh and I probably should update my repo before I draw any firm conclusions.</p>



<a name="126869883"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869883" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869883">(May 21 2018 at 12:27)</a>:</h4>
<p>yes we need it</p>



<a name="126869921"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869921" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869921">(May 21 2018 at 12:28)</a>:</h4>
<p>I think what we <em>don't</em> need is the second call to <code>kill_loans_out_of_scope</code></p>



<a name="126869922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869922">(May 21 2018 at 12:28)</a>:</h4>
<p>If we need it I don't see where we are currently using it</p>



<a name="126869925"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869925" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869925">(May 21 2018 at 12:28)</a>:</h4>
<p>I already was talking to <span class="user-mention" data-user-id="116107">@David Wood</span> about removing it</p>



<a name="126869926"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869926" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869926">(May 21 2018 at 12:28)</a>:</h4>
<p>(in the sense of, I don't see where we currently observe its effect)</p>



<a name="126869929"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869929" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869929">(May 21 2018 at 12:28)</a>:</h4>
<p>Anyway what brought me to investigate this</p>



<a name="126869932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869932">(May 21 2018 at 12:28)</a>:</h4>
<p>let me go double check but I believe that was important and could not be simulated with the existing <code>statement_effect</code></p>



<a name="126869935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869935">(May 21 2018 at 12:29)</a>:</h4>
<p>also, have you seen all the <span class="emoji emoji-1f438" title="frog">:frog:</span> deveopments <span class="user-mention" data-user-id="116083">@pnkfelix</span> ?</p>



<a name="126869941"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869941" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869941">(May 21 2018 at 12:29)</a>:</h4>
<p>is that I was thinking of tearing out <code>fn before_foo_effect</code>, and replacing it with new parameters to <code>fn statement_effect</code></p>



<a name="126869947"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869947" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869947">(May 21 2018 at 12:29)</a>:</h4>
<p>There's a PR in to remove the two calls to the expensive function.</p>



<a name="126869951"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869951" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869951">(May 21 2018 at 12:29)</a>:</h4>
<blockquote>
<p>is that I was thinking of tearing out <code>fn before_foo_effect</code>, and replacing it with new parameters to <code>fn statement_effect</code></p>
</blockquote>
<p>that..hmm. that sounds strictly worse to me?</p>



<a name="126869956"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869956" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869956">(May 21 2018 at 12:29)</a>:</h4>
<p>I guess my knee jerk reaction to a parameter is "no" though :)</p>



<a name="126869957"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869957" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869957">(May 21 2018 at 12:29)</a>:</h4>
<p>something like <code>enum Offset { BeforeEntry, BetweenEvalRhsAndAssignToLHS, After }</code>, and then have <code>fn statement_effect(from: Offset, upto: Offset);</code></p>



<a name="126869964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869964">(May 21 2018 at 12:29)</a>:</h4>
<p>I see</p>



<a name="126869966"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126869966" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126869966">(May 21 2018 at 12:30)</a>:</h4>
<p>it sounds kind of complex to reason about</p>



<a name="126870016"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870016">(May 21 2018 at 12:30)</a>:</h4>
<p>My issue is that right now I find the specification of what <code>before_statement_effect</code> quite confusing</p>



<a name="126870019"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870019" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870019">(May 21 2018 at 12:30)</a>:</h4>
<p>where do we use <code>After</code>?</p>



<a name="126870025"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870025" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870025">(May 21 2018 at 12:30)</a>:</h4>
<p>I think it actually maps quite well to the concept of start and mid points</p>



<a name="126870028"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870028" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870028">(May 21 2018 at 12:30)</a>:</h4>
<p>The intention is that the callers write down what scope of effect they are trying to capture</p>



<a name="126870029"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870029" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870029">(May 21 2018 at 12:30)</a>:</h4>
<p><code>before_statement_effect</code> is basically the "start" point and <code>statement_effect</code> is the "mid point"</p>



<a name="126870033"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870033" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870033">(May 21 2018 at 12:30)</a>:</h4>
<p>though really I think "mid point" is not the best term</p>



<a name="126870034"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870034">(May 21 2018 at 12:30)</a>:</h4>
<p>do they want the whole effect (in which case they pass <code>from: BeforeEntry, upto: After</code></p>



<a name="126870036"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870036">(May 21 2018 at 12:30)</a>:</h4>
<p>in that it's not a specific point, but rather a kind of "heisenberg range"</p>



<a name="126870044"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870044" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870044">(May 21 2018 at 12:31)</a>:</h4>
<p>or do they want to investigate the intermediate point after the RHS has been evaluated</p>



<a name="126870047"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870047" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870047">(May 21 2018 at 12:31)</a>:</h4>
<blockquote>
<p>or do they want to investigate the intermediate point after the RHS has been evaluated</p>
</blockquote>
<p>I'm not convinced that's a meaningful thing</p>



<a name="126870048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870048">(May 21 2018 at 12:31)</a>:</h4>
<p>in fact, i'm pretty convinced it's not</p>



<a name="126870051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870051">(May 21 2018 at 12:31)</a>:</h4>
<p>or, specifically what I mean is:</p>



<a name="126870055"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870055" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870055">(May 21 2018 at 12:31)</a>:</h4>
<p>there is no point in between evaluating the RHS and storing into the LHS</p>



<a name="126870057"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870057" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870057">(May 21 2018 at 12:31)</a>:</h4>
<p>Because we don't write to the RHS as an atomic action?</p>



<a name="126870058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870058">(May 21 2018 at 12:31)</a>:</h4>
<p>those happen simultaneously</p>



<a name="126870061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870061">(May 21 2018 at 12:32)</a>:</h4>
<p>this is what I meant by "heisenberg range" above :)</p>



<a name="126870098"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870098" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870098">(May 21 2018 at 12:32)</a>:</h4>
<p>I suppose that is true</p>



<a name="126870113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870113">(May 21 2018 at 12:33)</a>:</h4>
<p>I've seen the traffic about <span class="emoji emoji-1f438" title="frog">:frog:</span> but I have not had the chance to catch up with it</p>



<a name="126870119"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870119" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870119">(May 21 2018 at 12:33)</a>:</h4>
<p>I did see mention that it would affect whether we still need subprocess integration</p>



<a name="126870174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870174">(May 21 2018 at 12:34)</a>:</h4>
<p>Anyway I do agree we need something <em>more</em>. I just don't like the current API, or at least the current specification of the current API.</p>



<a name="126870190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870190">(May 21 2018 at 12:35)</a>:</h4>
<p>(Which of course I should have commented on back in December, I'm not saying that I'm faultless here)</p>



<a name="126870260"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870260" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870260">(May 21 2018 at 12:36)</a>:</h4>
<blockquote>
<p>I did see mention that it would affect whether we still need subprocess integration</p>
</blockquote>
<p>yes very much</p>



<a name="126870276"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870276" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870276">(May 21 2018 at 12:37)</a>:</h4>
<p>The other option I was considering was to replace whole-hog the uses of <code>mir::Location</code> underneath <code>rustc_mir::dataflow</code> and <code>rustc_mir::borrow_check</code> with some sort of <code>rustc_mir::dataflow::Location</code> type that would encode whether we were sitting <code>Before</code>, or <code>Amidst</code>, or <code>After</code>.</p>



<a name="126870339"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870339" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870339">(May 21 2018 at 12:39)</a>:</h4>
<p>but I wanted to make it easy for non-borrow-check clients to continue using dataflow. Which means giving some easy path for recreating the effect of a whole statement, without trying to model the fuzzy space modeled by <code>Mid</code> (or <code>Amidst</code>, whatever).</p>



<a name="126870347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870347">(May 21 2018 at 12:39)</a>:</h4>
<p>anyway I guess I will now review the backlog to try to determine what is going on.</p>



<a name="126870349"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870349" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870349">(May 21 2018 at 12:39)</a>:</h4>
<p>the TL;DR is that we moved from differential-dataflow to <span class="emoji emoji-1f438" title="frog">:frog:</span> and — as a side-effect — we can now integrate polonius as a library quite easily. Probably more easily than an executable.</p>



<a name="126870490"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870490" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870490">(May 21 2018 at 12:43)</a>:</h4>
<blockquote>
<p>The other option I was considering was to replace whole-hog the uses of <code>mir::Location</code> underneath <code>rustc_mir::dataflow</code> and <code>rustc_mir::borrow_check</code> with some sort of <code>rustc_mir::dataflow::Location</code> type that would encode whether we were sitting <code>Before</code>, or <code>Amidst</code>, or <code>After</code>.</p>
</blockquote>
<p>this already exists. It's called <a href="https://github.com/rust-lang/rust/blob/21b536704574061cebe431582116b6f91ae5b983/src/librustc_mir/borrow_check/location.rs#L25-L28" target="_blank" title="https://github.com/rust-lang/rust/blob/21b536704574061cebe431582116b6f91ae5b983/src/librustc_mir/borrow_check/location.rs#L25-L28"><code>LocationIndex</code></a>.</p>



<a name="126870554"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870554" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870554">(May 21 2018 at 12:44)</a>:</h4>
<p>I want to re-iterate that I don't think we want/need an <code>After</code> point though =)</p>



<a name="126870890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870890">(May 21 2018 at 12:52)</a>:</h4>
<p>if your meaning is that an <code>(After, loc)</code>should be equivalent in meaning to a <code>(Before, succ(loc))</code>, then I understand that and agree it would be a redundancy</p>



<a name="126870892"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126870892" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126870892">(May 21 2018 at 12:52)</a>:</h4>
<p>yeah pretty much that</p>



<a name="126961932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126961932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126961932">(May 23 2018 at 06:01)</a>:</h4>
<blockquote>
<p>did we ever ended up with graphviz visualizations for facts?</p>
</blockquote>
<p>@qmx: to the best of my knowledge, no</p>



<a name="126964932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126964932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126964932">(May 23 2018 at 07:45)</a>:</h4>
<p>not sure where i'm supposed to ask this, but what becomes of the SEME integration?</p>



<a name="126964964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126964964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126964964">(May 23 2018 at 07:46)</a>:</h4>
<p>last week's meeting niko mentioned that we'll be instead moving towards implementing that as a short term solution</p>



<a name="126967642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126967642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126967642">(May 23 2018 at 09:07)</a>:</h4>
<p>I <em>think</em> at this point niko has decided that SEME would be too much effort for too little gain</p>



<a name="126967776"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/126967776" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#126967776">(May 23 2018 at 09:10)</a>:</h4>
<p>yep, it's optimizing something that is 0% of the profile</p>



<a name="127030911"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127030911" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127030911">(May 24 2018 at 14:20)</a>:</h4>
<p>Hey: Was part of the expected effects of NLL to actually pin down a particular destruction order for the variables in <code>let (x, y) = ...;</code> ?</p>



<a name="127030950"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127030950" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127030950">(May 24 2018 at 14:21)</a>:</h4>
<p>Historically the AST-borrowck has treated those as expiring at "the same time", in terms of saying e.g. if <code>y</code> is <code>Drop</code> <em>and</em> holds a borrow of <code>x</code>, that's an error. Even though technically we could allow that.</p>



<a name="127031002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031002">(May 24 2018 at 14:22)</a>:</h4>
<p>It seems that since MIR-borrowck operates on the control flow, it has stopped treating <em>that</em> like an error. (But having <code>x</code> be <code>Drop</code> and hold a borrow of <code>y</code> continues to be an error.</p>



<a name="127031019"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031019" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031019">(May 24 2018 at 14:23)</a>:</h4>
<p>My question is: Do we want to try to prevent this? (not sure exactly how we would; perhaps with more FalseEdges analogous to what we did for <code>match</code> in order to keep our options open for the future...)</p>



<a name="127031112"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031112" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031112">(May 24 2018 at 14:24)</a>:</h4>
<p>((doing that might cause code explosion though...))</p>



<a name="127031114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031114">(May 24 2018 at 14:24)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> a good point. I would be ok with pinning down a dtor order: after all, it's observable in other ways</p>



<a name="127031147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031147">(May 24 2018 at 14:25)</a>:</h4>
<p>yeah the only argument I can see against it is that some people may see AST-borrowck's current strictness (of requiring separate <code>let</code> bindings when drop order matters) as a feature, not a bug...</p>



<a name="127031161"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031161" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031161">(May 24 2018 at 14:25)</a>:</h4>
<p>(sort of like how some people like requiring <code>let mut</code> back during the mutapocalypse)</p>



<a name="127031215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031215">(May 24 2018 at 14:26)</a>:</h4>
<p>Though this seems somewhat less likely to actually catch bugs in the real world</p>



<a name="127031267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127031267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127031267">(May 24 2018 at 14:27)</a>:</h4>
<p>I guess I'll open an issue just to have something to reference from Github when having discussion in comment threads</p>



<a name="127033309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127033309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127033309">(May 24 2018 at 15:12)</a>:</h4>
<p>Filed as <a href="https://github.com/rust-lang/rust/issues/51036" target="_blank" title="https://github.com/rust-lang/rust/issues/51036">rust-lang/rust#51036</a></p>



<a name="127050452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050452">(May 24 2018 at 21:22)</a>:</h4>
<p>hey niko do you have a second to double check something with me?</p>



<a name="127050477"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050477" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050477">(May 24 2018 at 21:23)</a>:</h4>
<p>or maybe I'll ask Zoxc</p>



<a name="127050536"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050536" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050536">(May 24 2018 at 21:24)</a>:</h4>
<p>the basic question is: the comments in <a href="https://github.com/rust-lang/rust/blob/master/src/test/ui/generator/dropck.rs" target="_blank" title="https://github.com/rust-lang/rust/blob/master/src/test/ui/generator/dropck.rs">https://github.com/rust-lang/rust/blob/master/src/test/ui/generator/dropck.rs</a> imply (to me) that a use-after-free was observed, or at least posited to exist</p>



<a name="127050550"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050550" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050550">(May 24 2018 at 21:25)</a>:</h4>
<p>But I don't think it would have under Rust's semantics for drop order in <code>let (cell, mut gen);</code></p>



<a name="127050559"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050559" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050559">(May 24 2018 at 21:25)</a>:</h4>
<p>namely, the final comment says "drops the RefCell and then the Ref, leading to use-after-free"</p>



<a name="127050610"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050610" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050610">(May 24 2018 at 21:26)</a>:</h4>
<p>but for that to happen, the drop order would need to be: drop the <code>cell</code> <em>before</em> the <code>gen</code>. And that implies the declaration should have been <code>let (mut gen, cell);</code></p>



<a name="127050717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050717">(May 24 2018 at 21:29)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> not sure :)</p>



<a name="127050951"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127050951" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127050951">(May 24 2018 at 21:34)</a>:</h4>
<p>okay. All I know is that if I switch the declaration order to <code>let (mut gen, cell);</code>, we start seeing the expected errors under NLL.</p>



<a name="127051065"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127051065" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127051065">(May 24 2018 at 21:37)</a>:</h4>
<p>in most of these cases NLL is correct :)</p>



<a name="127051068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127051068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127051068">(May 24 2018 at 21:37)</a>:</h4>
<p>since it has the actual executable code to analyze...</p>



<a name="127051072"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127051072" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127051072">(May 24 2018 at 21:37)</a>:</h4>
<p>...sometimes that code is odd though</p>



<a name="127051109"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127051109" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127051109">(May 24 2018 at 21:38)</a>:</h4>
<p>(doens't sound like the instance here)</p>



<a name="127051124"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127051124" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127051124">(May 24 2018 at 21:38)</a>:</h4>
<p>most of those cases where I am grumpy have to do with the temporaries in tail position</p>



<a name="127123727"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127123727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127123727">(May 26 2018 at 10:33)</a>:</h4>
<p>Spoke a bit about Polonius and NLL with RalfJ at rusfest paris and they mentioned they were interested in it, relating to their Coq formal work :)</p>



<a name="127125009"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127125009" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127125009">(May 26 2018 at 11:21)</a>:</h4>
<p>I'm jealous of you RustFesters!</p>



<a name="127127595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127127595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127127595">(May 26 2018 at 13:07)</a>:</h4>
<p>:)</p>



<a name="127129397"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127129397" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127129397">(May 26 2018 at 14:09)</a>:</h4>
<p>Hello NLL friends! This generates an error with and without NLL, but we aren't sure it should. Any opinions one way or the other?:</p>
<div class="codehilite"><pre><span></span><span class="cp">#![feature(nll)]</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">next</span><span class="o">&lt;</span><span class="na">&#39;buf</span><span class="o">&gt;</span><span class="p">(</span><span class="n">buffer</span>: <span class="kp">&amp;</span><span class="na">&#39;buf</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="nb">String</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="na">&#39;buf</span><span class="w"> </span><span class="kt">str</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">loop</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="kd">let</span><span class="w"> </span><span class="n">event</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">parse</span><span class="p">(</span><span class="n">buffer</span><span class="p">);</span><span class="w"></span>

<span class="w">        </span><span class="k">if</span><span class="w"> </span><span class="kc">true</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="k">return</span><span class="w"> </span><span class="n">event</span><span class="p">;</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">parse</span><span class="o">&lt;</span><span class="na">&#39;buf</span><span class="o">&gt;</span><span class="p">(</span><span class="n">_buffer</span>: <span class="kp">&amp;</span><span class="na">&#39;buf</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="nb">String</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="na">&#39;buf</span><span class="w"> </span><span class="kt">str</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">unimplemented</span><span class="o">!</span><span class="p">()</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{}</span><span class="w"></span>
</pre></div>


<div class="codehilite"><pre><span></span>error[E0499]: cannot borrow `*buffer` as mutable more than once at a time
 --&gt; src/main.rs:5:27
  |
5 |         let event = parse(buffer);
  |                           ^^^^^^ mutable borrow starts here in previous iteration of loop
  |
note: borrowed value must be valid for the lifetime &#39;buf as defined on the function body at 3:1...
 --&gt; src/main.rs:3:1
  |
3 | fn next&lt;&#39;buf&gt;(buffer: &amp;&#39;buf mut String) -&gt; &amp;&#39;buf str {
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
</pre></div>



<a name="127129462"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127129462" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127129462">(May 26 2018 at 14:11)</a>:</h4>
<p>seeing as how <code>event</code> should either leave the loop or be thrown away before the next iteration</p>



<a name="127199364"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127199364" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127199364">(May 28 2018 at 10:24)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> this should throw an error (for now) but this error should eventually go away. This is precisely a case where "Location sensitivity" is needed, but we removed that feature in the name of performance — once polonius support lands, though, this code would be accepted. That may or may not be before the edition.</p>



<a name="127199375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127199375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127199375">(May 28 2018 at 10:25)</a>:</h4>
<p>It's actually a nice reduced test case, maybe you can file an issue? It'd be good to add to the test suite.</p>



<a name="127210838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127210838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127210838">(May 28 2018 at 15:35)</a>:</h4>
<blockquote>
<p>maybe you can file an issue?</p>
</blockquote>
<p>Done as <a href="https://github.com/rust-lang/rust/issues/51132" target="_blank" title="https://github.com/rust-lang/rust/issues/51132">https://github.com/rust-lang/rust/issues/51132</a>. Thanks!</p>



<a name="127211065"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211065" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211065">(May 28 2018 at 15:40)</a>:</h4>
<p>Would anyone care to take a stab at what "location sensitivity" is in 1-3 sentences? I'm pretty sure I'd botch it. Trying to circle back to answer the original SO question that prompted that last example.</p>



<a name="127211206"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211206" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211206">(May 28 2018 at 15:44)</a>:</h4>
<p>in the context of your example: the value <code>event</code> only has to have the lifetime <code>'buf</code> <em>conditionally</em> — at the return point which may or may not execute. But when we are "location insensitive", we just track the lifetime that <code>event</code> must have <em>anywhere</em>, without considering <em>where</em> that lifetime must hold. In this case, that means we make it hold <em>everywhere</em>, which is why you get a compilation failure.</p>



<a name="127211353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211353">(May 28 2018 at 15:49)</a>:</h4>
<p>I see. So the lifetime of the <code>event</code> inside the <code>if</code> block needs to be <code>'buf</code>, but the lifetime of the <code>event</code> after the <code>if</code> doesn't. Does "anywhere" even mean outside the loop?</p>



<a name="127211436"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211436" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211436">(May 28 2018 at 15:51)</a>:</h4>
<p>yes</p>



<a name="127211479"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211479" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211479">(May 28 2018 at 15:52)</a>:</h4>
<p>so, one subtle thing is that the current analysis is location sensitive in <em>one respect</em> —</p>



<a name="127211480"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211480" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211480">(May 28 2018 at 15:52)</a>:</h4>
<p>where the borrow takes place</p>



<a name="127211489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211489">(May 28 2018 at 15:52)</a>:</h4>
<p>but the <em>length</em> of the borrow is not</p>



<a name="127211491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211491">(May 28 2018 at 15:52)</a>:</h4>
<p>this is why you can often fix bugs by doing</p>



<a name="127211506"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211506" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211506">(May 28 2018 at 15:53)</a>:</h4>
<p>that is, by convering:</p>
<div class="codehilite"><pre><span></span>let p = &amp;x;
if condition(p) {
  return p;
}
</pre></div>


<p>into:</p>
<div class="codehilite"><pre><span></span>let p = &amp;x;
if condition(p) {
  return &amp;x; // NB fresh borrow
}
</pre></div>



<a name="127211507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211507">(May 28 2018 at 15:53)</a>:</h4>
<blockquote>
<p>this is why you can often fix bugs by doing</p>
</blockquote>
<p>er, I mean "workaround" the problem, really</p>



<a name="127211560"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127211560" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127211560">(May 28 2018 at 15:54)</a>:</h4>
<p>heh, I like it</p>



<a name="127221112"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221112" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221112">(May 28 2018 at 21:00)</a>:</h4>
<p>does someone know how to pass <code>compare-mode=nll</code> when using <code>x.py</code>?</p>



<a name="127221337"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221337" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221337">(May 28 2018 at 21:09)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> hmm I think you may have to run with <code>-v</code> and add the argument manually</p>



<a name="127221400"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221400" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221400">(May 28 2018 at 21:10)</a>:</h4>
<p>how is that?</p>



<a name="127221415"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221415" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221415">(May 28 2018 at 21:11)</a>:</h4>
<p><code>x.py test -v src/test/ui</code>, in other words, and then see what gets output</p>



<a name="127221420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221420">(May 28 2018 at 21:11)</a>:</h4>
<p>there should be a call to a <code>compiletest</code> binary somewhere</p>



<a name="127221422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221422">(May 28 2018 at 21:11)</a>:</h4>
<p>but maybe we added a compare-mode to <code>x.py</code></p>



<a name="127221423"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221423" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221423">(May 28 2018 at 21:11)</a>:</h4>
<p>I can't remember</p>



<a name="127221430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221430">(May 28 2018 at 21:12)</a>:</h4>
<p>there's also this <a href="https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L704-L709" target="_blank" title="https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L704-L709">https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L704-L709</a></p>



<a name="127221431"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221431" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221431">(May 28 2018 at 21:12)</a>:</h4>
<p>if not, we could add one readily enough...</p>



<a name="127221471"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221471" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221471">(May 28 2018 at 21:12)</a>:</h4>
<p>but that will run on ci I guess</p>



<a name="127221473"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221473" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221473">(May 28 2018 at 21:12)</a>:</h4>
<p>I mean I can use to quickly test it</p>



<a name="127221477"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221477" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221477">(May 28 2018 at 21:12)</a>:</h4>
<p>better to use this one <a href="https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L649-L655" target="_blank" title="https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L649-L655">https://github.com/rust-lang/rust/blob/master/src/bootstrap/test.rs#L649-L655</a> I guess</p>



<a name="127221483"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221483" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221483">(May 28 2018 at 21:13)</a>:</h4>
<p>oh btw there is <code>./x.py test --rustc-args</code></p>



<a name="127221484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221484">(May 28 2018 at 21:13)</a>:</h4>
<p>which would prob suffice for a simple test :)</p>



<a name="127221536"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221536" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221536">(May 28 2018 at 21:14)</a>:</h4>
<p>you might be able to use <code>--test-args</code> for this?</p>



<a name="127221539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221539">(May 28 2018 at 21:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> try <code>--test-args '--compare-mode polonius'</code> and see if that works</p>



<a name="127221548"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221548" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221548">(May 28 2018 at 21:15)</a>:</h4>
<p>that is, <code>./x.py test src/test/ui --test-args '--compare-mode polonius'</code></p>



<a name="127221605"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221605" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221605">(May 28 2018 at 21:17)</a>:</h4>
<p>have already tried test-args but without quotes</p>



<a name="127221608"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221608" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221608">(May 28 2018 at 21:17)</a>:</h4>
<p>trying exactly that</p>



<a name="127221649"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127221649" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127221649">(May 28 2018 at 21:18)</a>:</h4>
<p>I guess we should move to #'compate-mode notes'</p>



<a name="127286972"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127286972" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127286972">(May 30 2018 at 03:09)</a>:</h4>
<p>A side anecdote... A few minutes ago, I was surprised to learn that this code works with NLL:</p>
<div class="codehilite"><pre><span></span><span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">foo</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">None</span><span class="p">;</span><span class="w"></span>
<span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">string1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;Hello&quot;</span><span class="p">.</span><span class="n">to_string</span><span class="p">();</span><span class="w"></span>
<span class="n">foo</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="o">&amp;</span><span class="n">string1</span><span class="p">);</span><span class="w"></span>
<span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">string2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;Goodbye&quot;</span><span class="p">.</span><span class="n">to_string</span><span class="p">();</span><span class="w"></span>
<span class="n">foo</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="o">&amp;</span><span class="n">string2</span><span class="p">);</span><span class="w"></span>
</pre></div>


<p>After reflection, I think my problem is that I have a preexisting mental model where the type of <code>foo</code> starts as <code>Option&lt;&amp;'static String&gt;</code>.  On the first assignment, it would be changing it's type to <code>Option&lt;&amp;'string1 String&gt;</code> and then to <code>Option&lt;&amp;'string2 String&gt;</code> at the second assignment. "Obviously" you can't change the type of a variable through assignment, so it makes "intuitive" sense that this would fail to compile.</p>
<p>To keep my mental model where the lifetime is part of the type and a type cannot change through assignment , the lifetime inside <code>foo</code> under NLL has to be more "fluid". It's now always the same thing (say <code>'a</code>), but the actual value of that <code>'a</code> changes depending on which line of code we are looking at (a.k.a. what actions have occurred to  the referred-to value).</p>
<p>Just thought I'd share; I wonder how other Rustaceans mental models compare and how they will be affected by NLL.</p>



<a name="127297701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127297701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127297701">(May 30 2018 at 08:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> there is actually a question mark for me about more-or-less this specific point with polonius. But a question: does it surprise you that this would work? (This works today)</p>
<div class="codehilite"><pre><span></span>let mut string1 = &quot;Hello&quot;.to_string();
let mut string2 = &quot;Goodbye&quot;.to_string();
let mut foo = None;
foo = Some(&amp;string1);
foo = Some(&amp;string2);
</pre></div>



<a name="127297770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127297770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127297770">(May 30 2018 at 08:57)</a>:</h4>
<p>That said, polonius does allow you to do things that might be surprising if you think too hard about them, and I've been wondering if we should dial it back. The motivation is to support stuff like this:</p>
<div class="codehilite"><pre><span></span>let mut x = 3;
let mut p = &amp;x;
let mut q = p;
let mut y = 4;
p = &amp;y; // at this point, p &quot;borrows&quot; y, and q &quot;borrows&quot; x
println(p);
y += 1; // key point: p is no longer in use, so y is not borrowed
prontln(q);
</pre></div>



<a name="127297817"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127297817" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127297817">(May 30 2018 at 08:58)</a>:</h4>
<p>But as a kind of side-effect we wind up permitting stuff like this, or at least we could if we are not careful:</p>
<div class="codehilite"><pre><span></span><span class="k">fn</span> <span class="nf">foo</span><span class="p">(</span><span class="k">mut</span><span class="w"> </span><span class="n">p</span>: <span class="kp">&amp;</span><span class="nb">&#39;static</span><span class="w"> </span><span class="kt">u32</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">22</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="n">p</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="n">y</span><span class="p">;</span><span class="w"> </span><span class="c1">// old value, and hence old regions, of `p` are not important</span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="127297820"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127297820" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127297820">(May 30 2018 at 08:58)</a>:</h4>
<p>I've been meaning to write up a blog post trying to dive into this specific point and see if we can draw a better line about which to support and which not.</p>



<a name="127302164"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127302164" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127302164">(May 30 2018 at 11:01)</a>:</h4>
<p>alright I was looking at the "-Z polonius" failures we saw earlier, and yeah for sure the Opt variant has slight differences from the Naive one</p>



<a name="127302575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127302575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127302575">(May 30 2018 at 11:14)</a>:</h4>
<blockquote>
<p>does it surprise you that this would work? (This works today)</p>
</blockquote>
<p>I don't feel like I am surprised by that, but it may just be because I'm used to current Rust. I think my mental model is that all the uses are scanned up-front and then a single lifetime is assigned. In that example, the type of <code>foo</code> would be <code>Option&lt;&amp;'string2 String&gt;</code>. <code>string1</code> can be shortened to fit that, and the implicit <code>'static</code> of the <code>None</code> can be as well.</p>



<a name="127302656"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127302656" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127302656">(May 30 2018 at 11:17)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> would it be interesting to have this, or some of these failures, in the polonius repo, and if so, under which form ? add the facts files  in "inputs" (but without enabling them in the <code>tests!</code>macro), or replicate those facts in the frontend, or something else ?</p>



<a name="127302722"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127302722" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127302722">(May 30 2018 at 11:19)</a>:</h4>
<blockquote>
<div class="codehilite"><pre><span></span><span class="k">fn</span> <span class="nf">foo</span><span class="p">(</span><span class="k">mut</span><span class="w"> </span><span class="n">p</span>: <span class="kp">&amp;</span><span class="nb">&#39;static</span><span class="w"> </span><span class="kt">u32</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">22</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="n">p</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="n">y</span><span class="p">;</span><span class="w"> </span><span class="c1">// old value, and hence old regions, of `p` are not important</span>
<span class="p">}</span><span class="w"></span>
</pre></div>


</blockquote>
<p>What I dislike about this is that it's really obvious that the "type" of <code>p</code> changes through assignment. It also kind of goes against the idea I have that user-specified lifetime annotations should be "important" (<a href="https://github.com/rust-lang/rust/issues/47184" target="_blank" title="https://github.com/rust-lang/rust/issues/47184">https://github.com/rust-lang/rust/issues/47184</a>) I also understand a bit better why that issues exists to start with.</p>



<a name="127302777"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127302777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127302777">(May 30 2018 at 11:20)</a>:</h4>
<p>On the flip side, I can see why writing this code is super useful</p>



<a name="127305223"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305223" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305223">(May 30 2018 at 12:33)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> well, they would be "imported", but only at the point of the first assignment (in this case, that is at the point where fn is called). But I don't disagree.</p>



<a name="127305267"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305267" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305267">(May 30 2018 at 12:34)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> probably — now that integration has landed, we should do a bit of investigation (first and foremost) into the failing tests</p>



<a name="127305293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305293">(May 30 2018 at 12:35)</a>:</h4>
<p>yeah that was was I doing during lunch break, investigating where naive/opt start differing in the ui test <a href="http://issue-31567.rs" target="_blank" title="http://issue-31567.rs">issue-31567.rs</a></p>



<a name="127305296"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305296" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305296">(May 30 2018 at 12:35)</a>:</h4>
<p>I suspect we can restore more intuitive behavior by tweaking the definition of <code>region_live_at</code> — for example, the regions in a variable might be live everywhere that a variable is in scope. But I don't want to do any of that until we hvae a good test suite to judge the effects.</p>



<a name="127305301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305301">(May 30 2018 at 12:35)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> do they, in fact, differ?</p>



<a name="127305302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305302">(May 30 2018 at 12:35)</a>:</h4>
<p>absolutely</p>



<a name="127305307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305307">(May 30 2018 at 12:35)</a>:</h4>
<p>also, do we have the ability to set the algorithm with rustc?</p>



<a name="127305309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305309">(May 30 2018 at 12:35)</a>:</h4>
<p>(via env var)</p>



<a name="127305330"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305330" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305330">(May 30 2018 at 12:36)</a>:</h4>
<p>I had talked about adding that, not sure if it got done</p>



<a name="127305351"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305351" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305351">(May 30 2018 at 12:36)</a>:</h4>
<blockquote>
<p>absolutely</p>
</blockquote>
<p>interesting</p>



<a name="127305367"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305367" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305367">(May 30 2018 at 12:36)</a>:</h4>
<p>/me has to divide how to parcel up his day today</p>



<a name="127305380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305380">(May 30 2018 at 12:37)</a>:</h4>
<p>of course, that's why I was investigating this on my own first, so that you don't need to look at it yet :)</p>



<a name="127305430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127305430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127305430">(May 30 2018 at 12:38)</a>:</h4>
<p>(there are a couple PRs in flight, but I feel I've seen a PR from <span class="user-mention" data-user-id="116109">@Vytautas Astrauskas</span> related to an env var to select the algorithm, but maybe was it just about <a href="https://github.com/rust-lang-nursery/polonius/pull/60/commits/02dfb90de59256974549e627acfe640230955f92" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/60/commits/02dfb90de59256974549e627acfe640230955f92">polonius</a>)</p>



<a name="127307293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127307293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127307293">(May 30 2018 at 13:22)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> this doesn't work, which seems inconsistent:</p>
<div class="codehilite"><pre><span></span><span class="k">struct</span> <span class="nc">W</span><span class="o">&lt;</span><span class="na">&#39;a</span><span class="o">&gt;</span><span class="p">(</span><span class="o">&amp;</span><span class="na">&#39;a</span><span class="w"> </span><span class="kt">u32</span><span class="p">);</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">foo</span><span class="p">(</span><span class="k">mut</span><span class="w"> </span><span class="n">p</span>: <span class="nc">W</span><span class="o">&lt;</span><span class="nb">&#39;static</span><span class="o">&gt;</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">22</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="n">p</span><span class="p">.</span><span class="mi">0</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="n">y</span><span class="p">;</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="127307549"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127307549" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Vytautas Astrauskas [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127307549">(May 30 2018 at 13:28)</a>:</h4>
<blockquote>
<p>(there are a couple PRs in flight, but I feel I've seen a PR from <span class="user-mention" data-user-id="116109">@Vytautas Astrauskas</span> related to an env var to select the algorithm, but maybe was it just about <a href="https://github.com/rust-lang-nursery/polonius/pull/60/commits/02dfb90de59256974549e627acfe640230955f92" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/60/commits/02dfb90de59256974549e627acfe640230955f92">polonius</a>)</p>
</blockquote>
<p>Rustc has DatafrogOpt <a href="https://github.com/rust-lang/rust/blob/20af72b943527d584df4b99e157262f9b297b3e4/src/librustc_mir/borrow_check/nll/mod.rs#L159-L162" target="_blank" title="https://github.com/rust-lang/rust/blob/20af72b943527d584df4b99e157262f9b297b3e4/src/librustc_mir/borrow_check/nll/mod.rs#L159-L162">hard coded</a>. We could change it to something like:</p>
<div class="codehilite"><pre><span></span><span class="kd">let</span><span class="w"> </span><span class="n">algorithm</span>: <span class="nc">Algorithm</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">env</span>::<span class="n">var</span><span class="p">(</span><span class="s">&quot;POLONIUS_ALGORITHM&quot;</span><span class="p">).</span><span class="n">unwrap_or</span><span class="p">(</span><span class="s">&quot;DatafrogOpt&quot;</span><span class="p">).</span><span class="n">into</span><span class="p">();</span><span class="w"></span>
</pre></div>


<p>However, for that we need a new version of polonius-engine to be released and it probably would make sense to land first all PRs that are currently in flight.</p>



<a name="127307873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127307873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127307873">(May 30 2018 at 13:36)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> indeed, we draw a distinction between "overwriting the variable" (<code>p = ...</code>) and updating part of it (<code>p.0 = ...</code>)</p>



<a name="127307914"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127307914" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127307914">(May 30 2018 at 13:38)</a>:</h4>
<p>Hm. I'll have to file that away for a future SO answer.</p>



<a name="127307956"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127307956" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127307956">(May 30 2018 at 13:38)</a>:</h4>
<p>well, that depends on the rules we ultimately settle on, I suppose :)</p>



<a name="127374370"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127374370" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127374370">(May 31 2018 at 17:52)</a>:</h4>
<p>What's the best issue for me to pick up and start on?</p>



<a name="127374943"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127374943" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127374943">(May 31 2018 at 18:03)</a>:</h4>
<p>good question...</p>



<a name="127374946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127374946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127374946">(May 31 2018 at 18:03)</a>:</h4>
<p>I think diagnostics + perf are still the order of the day</p>



<a name="127374990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127374990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127374990">(May 31 2018 at 18:04)</a>:</h4>
<p>I'm not sure within that, maybe <span class="user-mention" data-user-id="116083">@pnkfelix</span> has some suggestions</p>



<a name="127374996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127374996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127374996">(May 31 2018 at 18:04)</a>:</h4>
<p>I was hoping to do some more perf profiling and try to generate some leads</p>



<a name="127375282"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375282" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375282">(May 31 2018 at 18:10)</a>:</h4>
<p>I have a new table at the bottom of <a href="https://paper.dropbox.com/doc/NLL-stderr-diagnostic-deviations-KzroSvNgQ7lip3WQyiLTa" target="_blank" title="https://paper.dropbox.com/doc/NLL-stderr-diagnostic-deviations-KzroSvNgQ7lip3WQyiLTa">https://paper.dropbox.com/doc/NLL-stderr-diagnostic-deviations-KzroSvNgQ7lip3WQyiLTa</a></p>



<a name="127375297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375297">(May 31 2018 at 18:10)</a>:</h4>
<p>that lists all the diagnostic issues on that page that have a github issue</p>



<a name="127375325"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375325" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375325">(May 31 2018 at 18:11)</a>:</h4>
<p>as well as meta data: how many tests are affected by it? is there a PR to address it? and (just added) who is/was looking into it?</p>



<a name="127375377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375377">(May 31 2018 at 18:12)</a>:</h4>
<p>my strategy for resolving these issues</p>



<a name="127375388"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375388" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375388">(May 31 2018 at 18:12)</a>:</h4>
<p>has been to reverse engineer how the AST borrowck generates its notes/suggestions</p>



<a name="127375394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127375394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127375394">(May 31 2018 at 18:12)</a>:</h4>
<p>and then try to add something approximating that to MIR-borrowck. :)</p>



<a name="127376042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376042">(May 31 2018 at 18:27)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> do you have any suggestions for <span class="user-mention" data-user-id="116107">@David Wood</span> ?</p>



<a name="127376043"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376043" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376043">(May 31 2018 at 18:27)</a>:</h4>
<p>is there an "untaken" issue ?</p>



<a name="127376050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376050">(May 31 2018 at 18:27)</a>:</h4>
<p>most are untaken AFAIK</p>



<a name="127376055"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376055" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376055">(May 31 2018 at 18:27)</a>:</h4>
<p>I added a column to try to track that</p>



<a name="127376067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376067">(May 31 2018 at 18:27)</a>:</h4>
<p>but the best thing</p>



<a name="127376069"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376069" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376069">(May 31 2018 at 18:27)</a>:</h4>
<p>...</p>



<a name="127376074"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376074" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376074">(May 31 2018 at 18:27)</a>:</h4>
<p>might be for me to first skim through</p>



<a name="127376117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376117">(May 31 2018 at 18:28)</a>:</h4>
<p>to make some guess as to which ones are good starter issues, maybe</p>



<a name="127376176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376176">(May 31 2018 at 18:29)</a>:</h4>
<p>Sounds good.</p>



<a name="127376786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376786">(May 31 2018 at 18:39)</a>:</h4>
<p>hey actually <span class="user-mention" data-user-id="116107">@David Wood</span> , I reopened <a href="https://github.com/rust-lang/rust/issues/46983" target="_blank" title="https://github.com/rust-lang/rust/issues/46983">https://github.com/rust-lang/rust/issues/46983</a></p>



<a name="127376838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376838">(May 31 2018 at 18:40)</a>:</h4>
<p><span class="user-mention" data-user-id="116107">@David Wood</span> so that might be a great place to start, since you're already familiar with it</p>



<a name="127376858"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127376858" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127376858">(May 31 2018 at 18:40)</a>:</h4>
<p>Oh yeah, forgot I saw that email, will look into that.</p>



<a name="127506334"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127506334" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127506334">(Jun 03 2018 at 15:31)</a>:</h4>
<p>boooring. where's all the hard work everyone else is doing for me to watch. <span class="emoji emoji-1f607" title="innocent">:innocent:</span></p>



<a name="127511165"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127511165" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127511165">(Jun 03 2018 at 18:34)</a>:</h4>
<p>clearly we each need to make a Twitch channel</p>



<a name="127515967"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127515967" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127515967">(Jun 03 2018 at 21:34)</a>:</h4>
<p>I'd be down for a "Twitch codes the borrow checker" stream. Especially to watch the competing masses construct complex code</p>



<a name="127516362"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127516362" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127516362">(Jun 03 2018 at 21:49)</a>:</h4>
<p>there was a twitch stream of coding rust in ruby using helix over the weekend</p>



<a name="127620960"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127620960" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127620960">(Jun 05 2018 at 20:29)</a>:</h4>
<p>is there somebody else on Linux getting cannot allocate memory errors when compiling rustc?</p>



<a name="127620964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127620964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127620964">(Jun 05 2018 at 20:29)</a>:</h4>
<div class="codehilite"><pre><span></span>error: could not exec the linker `cc`
  |
  = note: Cannot allocate memory (os error 12)
  = note: &quot;cc&quot; &quot;-Wl,--as-needed&quot; &quot;-Wl,-z,noexecstack&quot; &quot;-m64&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc0-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc1-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc10-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc11-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc12-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc13-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc14-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc15-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc2-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc3-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc4-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc5-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc6-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc7-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc8-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.rustc9-b84aba51d8fa261656fb8626e42ec5b7.rs.rcgu.o&quot; &quot;-o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/librustc-e895ca9e7240a850.so&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.crate.metadata.rcgu.o&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps/rustc-e895ca9e7240a850.crate.allocator.rcgu.o&quot; &quot;-Wl,-z,relro,-z,now&quot; &quot;-Wl,-O1&quot; &quot;-nodefaultlibs&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/release/deps&quot; &quot;-L&quot; &quot;/usr/lib&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/build/backtrace-sys-e9110a0f73074a74/out&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/build/miniz-sys-a6962d6eb47c5537/out&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib&quot; &quot;-l&quot; &quot;test-818ff740b2707f00&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib&quot; &quot;-l&quot; &quot;term-b839a5796ea44350&quot; &quot;-Wl,-Bstatic&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libflate2-c17c83ac42687712.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libminiz_sys-9d2624e9eb4a622b.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libbacktrace-a35747a5a8069ba9.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libbacktrace_sys-1322fd8632ba970e.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/librustc_demangle-b3681afb8e962366.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/librustc_apfloat-80c82ead1538fe96.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libchalk_engine-58cfea5e91374964.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libchalk_macros-aad115bd8a7dd7b8.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/liblazy_static-51c2a57e338b5928.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-Wl,-Bdynamic&quot; &quot;-l&quot; &quot;proc_macro-bfb43a03f28a1a2b&quot; &quot;-Wl,-Bstatic&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libjobserver-0f76c961320be96e.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-Wl,-Bdynamic&quot; &quot;-l&quot; &quot;syntax-d3b388d855044135&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;rustc_errors-a62036a28f5fe0d1&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;syntax_pos-2a0bc4bd5ca0d03f&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;rustc_target-14ad2d7f44b20bbc&quot; &quot;-Wl,-Bstatic&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libpolonius_engine-73a5ff10d0da308d.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-Wl,--whole-archive&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libdatafrog-6bd5fdf8a4c09e7e.rlib&quot; &quot;-Wl,--no-whole-archive&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-Wl,-Bdynamic&quot; &quot;-l&quot; &quot;graphviz-c0b3d3295583df0b&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;fmt_macros-05d9a5117f1b8b6a&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;arena-268a49b49dfb8f2f&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;rustc_data_structures-d03d75bec68473fe&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;rustc_cratesio_shim-e967eee6857a2363&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-unknown-linux-gnu/release/deps&quot; &quot;-l&quot; &quot;serialize-b1c71ab5580e556c&quot; &quot;-Wl,--start-group&quot; &quot;-L&quot; &quot;/home/santiago/src/oss/rust-perf/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib&quot; &quot;-l&quot; &quot;std-267ac0a0e10e341c&quot; &quot;-Wl,--end-group&quot; &quot;-Wl,-Bstatic&quot; &quot;/tmp/rustc.vzQhQqLNNJtM/libcompiler_builtins-371c588c1a3805de.rlib&quot; &quot;-Wl,-Bdynamic&quot; &quot;-l&quot; &quot;unwind&quot; &quot;-l&quot; &quot;util&quot; &quot;-l&quot; &quot;util&quot; &quot;-l&quot; &quot;dl&quot; &quot;-l&quot; &quot;rt&quot; &quot;-l&quot; &quot;pthread&quot; &quot;-l&quot; &quot;gcc_s&quot; &quot;-l&quot; &quot;c&quot; &quot;-l&quot; &quot;m&quot; &quot;-l&quot; &quot;rt&quot; &quot;-l&quot; &quot;pthread&quot; &quot;-l&quot; &quot;util&quot; &quot;-l&quot; &quot;util&quot; &quot;-shared&quot; &quot;-Wl,-rpath,$ORIGIN/../lib&quot;

error: aborting due to previous error

error: Could not compile `rustc`.
</pre></div>



<a name="127621032"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127621032" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127621032">(Jun 05 2018 at 20:30)</a>:</h4>
<p>it's happening me following <a href="https://gist.github.com/nikomatsakis/45e81ac4cfcf21c665176e3e2907f40e" target="_blank" title="https://gist.github.com/nikomatsakis/45e81ac4cfcf21c665176e3e2907f40e">https://gist.github.com/nikomatsakis/45e81ac4cfcf21c665176e3e2907f40e</a></p>



<a name="127621035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127621035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127621035">(Jun 05 2018 at 20:30)</a>:</h4>
<p>8GB of RAM here</p>



<a name="127621036"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/127621036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#127621036">(Jun 05 2018 at 20:30)</a>:</h4>
<p>:P</p>



<a name="128031156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128031156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Reed Koser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128031156">(Jun 13 2018 at 21:31)</a>:</h4>
<p>At this point, people should probably consider anything assigned to me "soft unassigned." I'll be around on Zulip and IRC to answer questions, but realistically I only have about an hour a day to work on side projects and that's just not enough time to really get in the zone with <code>rustc</code> code. I'll have more time after mid-August or so to dive back in though =D</p>



<a name="128121009"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128121009" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128121009">(Jun 15 2018 at 13:56)</a>:</h4>
<blockquote>
<p>help: consider changing this to be a mutable reference: <code>&amp;mut elf</code></p>
</blockquote>
<p>Any idea why this message is <code>elf</code>?</p>



<a name="128125230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125230">(Jun 15 2018 at 15:23)</a>:</h4>
<p>I wanted to let you know that we (Uruguay) won against Egypt <span class="emoji emoji-1f604" title="smile">:smile:</span></p>



<a name="128125236"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125236" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125236">(Jun 15 2018 at 15:23)</a>:</h4>
<p>Here's the repro:</p>
<div class="codehilite"><pre><span></span><span class="cp">#![feature(nll, arbitrary_self_types)]</span><span class="w"></span>

<span class="k">use</span><span class="w"> </span><span class="n">std</span>::<span class="n">rc</span>::<span class="n">Rc</span><span class="p">;</span><span class="w"></span>

<span class="k">struct</span> <span class="nc">Combine</span><span class="p">(</span><span class="kt">u8</span><span class="p">);</span><span class="w"></span>

<span class="k">impl</span><span class="w"> </span><span class="n">Combine</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">fn</span> <span class="nf">poll</span><span class="p">(</span><span class="bp">self</span>: <span class="nc">Rc</span><span class="o">&lt;</span><span class="n">Self</span><span class="o">&gt;</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="n">drop</span><span class="p">(</span><span class="bp">self</span><span class="p">);</span><span class="w"></span>
<span class="w">        </span><span class="bp">self</span><span class="p">.</span><span class="mi">0</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{}</span><span class="w"></span>
</pre></div>



<a name="128125297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125297">(Jun 15 2018 at 15:24)</a>:</h4>
<blockquote>
<p>I wanted to let you know that we (Uruguay) won against Egypt <span class="emoji emoji-1f604" title="smile">:smile:</span></p>
</blockquote>
<p>🇺🇾</p>



<a name="128125311"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125311" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125311">(Jun 15 2018 at 15:24)</a>:</h4>
<p><span class="emoji emoji-1f604" title="smile">:smile:</span></p>



<a name="128125343"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125343" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125343">(Jun 15 2018 at 15:25)</a>:</h4>
<p>here football is more than a passion</p>



<a name="128125347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125347">(Jun 15 2018 at 15:25)</a>:</h4>
<p>there's no people in the street in matches like this</p>



<a name="128125359"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125359" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125359">(Jun 15 2018 at 15:25)</a>:</h4>
<p>everyone is watching the match</p>



<a name="128125435"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128125435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128125435">(Jun 15 2018 at 15:26)</a>:</h4>
<p>haha a goal at the last minute :D</p>



<a name="128127309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127309">(Jun 15 2018 at 16:07)</a>:</h4>
<p><span class="emoji emoji-2764" title="heart">:heart:</span> is the best way to win <span class="emoji emoji-1f604" title="smile">:smile:</span></p>



<a name="128127315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127315">(Jun 15 2018 at 16:07)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> where are you from?</p>



<a name="128127322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127322">(Jun 15 2018 at 16:07)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> France</p>



<a name="128127366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127366">(Jun 15 2018 at 16:08)</a>:</h4>
<p>good luck!, France is a great team</p>



<a name="128127378"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127378" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127378">(Jun 15 2018 at 16:08)</a>:</h4>
<p>we like Antoine a lot, he is a bit uruguayan <span class="emoji emoji-1f604" title="smile">:smile:</span></p>



<a name="128127389"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127389" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127389">(Jun 15 2018 at 16:08)</a>:</h4>
<p>if you're really into football you probably know why :)</p>



<a name="128127399"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128127399" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128127399">(Jun 15 2018 at 16:09)</a>:</h4>
<p>:D good luck to you / Uruguay as well :)</p>



<a name="128129949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128129949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128129949">(Jun 15 2018 at 17:04)</a>:</h4>
<p>I filed <a href="https://github.com/rust-lang/rust/issues/51578" target="_blank" title="https://github.com/rust-lang/rust/issues/51578">https://github.com/rust-lang/rust/issues/51578</a> for my elves</p>



<a name="128172877"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128172877" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128172877">(Jun 16 2018 at 15:59)</a>:</h4>
<p>how can I generate the inputs for a crate?</p>



<a name="128172926"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128172926" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128172926">(Jun 16 2018 at 16:00)</a>:</h4>
<p>the doc just shows the way for single rs code</p>



<a name="128195020"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128195020" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128195020">(Jun 17 2018 at 06:37)</a>:</h4>
<p>you can also pass the flags to cargo rustc</p>



<a name="128195553"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128195553" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128195553">(Jun 17 2018 at 06:59)</a>:</h4>
<p>I will make a PR to add that to the readme</p>



<a name="128195908"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128195908" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128195908">(Jun 17 2018 at 07:13)</a>:</h4>
<p><a href="https://github.com/rust-lang-nursery/polonius/pull/71" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/71">https://github.com/rust-lang-nursery/polonius/pull/71</a></p>



<a name="128196331"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128196331" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128196331">(Jun 17 2018 at 07:30)</a>:</h4>
<p>@lqd thank you :)</p>



<a name="128198413"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128198413" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128198413">(Jun 17 2018 at 08:59)</a>:</h4>
<p>np</p>



<a name="128224248"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224248" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224248">(Jun 18 2018 at 01:44)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> the “elf” thing is probably due to a royal mess of a hack in check_access_permissions which PR 51275 does a big rewrite of</p>



<a name="128224250"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224250" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224250">(Jun 18 2018 at 01:44)</a>:</h4>
<p>I will need to look into how that PR handles your test case</p>



<a name="128224271"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224271" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224271">(Jun 18 2018 at 01:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> cool. Then you get a free bug to close :-)</p>



<a name="128224322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224322">(Jun 18 2018 at 01:46)</a>:</h4>
<p>Which is now at 18x <span class="emoji emoji-1f606" title="laughing">:laughing:</span></p>



<a name="128224360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224360">(Jun 18 2018 at 01:47)</a>:</h4>
<p>But it’s code that looks like this:</p>



<a name="128224362"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224362" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224362">(Jun 18 2018 at 01:47)</a>:</h4>
<p>if let Ok(src) =<br>
                                    self.tcx.sess.codemap().span_to_snippet(sp) {<br>
                                        to_suggest_span = src[1..].to_string();<br>
                                };</p>



<a name="128224412"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224412" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224412">(Jun 18 2018 at 01:48)</a>:</h4>
<p>Because it assumed the first character was a ‘&amp;’ that it was chopping off</p>



<a name="128224436"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224436" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224436">(Jun 18 2018 at 01:49)</a>:</h4>
<p>I actually ended deciding to keep a similar strategy, rather than trying to reconstruct the type as the user wrote it. But I should probably check or at least assert that the first character actually <em>is</em> a ‘&amp;’</p>



<a name="128224582"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128224582" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128224582">(Jun 18 2018 at 01:54)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> the span can be more specific to <code>self</code> instead of split the string from raw span_str</p>



<a name="128225056"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128225056" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128225056">(Jun 18 2018 at 02:10)</a>:</h4>
<blockquote>
<p>to_suggest_span = src[1..].to_string();</p>
</blockquote>
<p>I kind of figured it was something like that, but darned if I knew where to find it.</p>



<a name="128452323"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128452323" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128452323">(Jun 22 2018 at 03:02)</a>:</h4>
<p>For those us of playing along at home, what is "mois"?</p>



<a name="128452753"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128452753" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128452753">(Jun 22 2018 at 03:19)</a>:</h4>
<p>collection of <code>MoveOutIndex</code> <span class="emoji emoji-1f642" title="simple smile">:simple_smile:</span></p>



<a name="128489892"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128489892" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128489892">(Jun 22 2018 at 19:39)</a>:</h4>
<p>I was wrong. My guess was "method of interest"</p>



<a name="128579778"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128579778" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128579778">(Jun 25 2018 at 02:52)</a>:</h4>
<p>Thought experiment: does the MIR-based borrowck remove the need for (mutable?) reborrowing?</p>



<a name="128609878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128609878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128609878">(Jun 25 2018 at 16:44)</a>:</h4>
<p>There are now <a href="https://stackoverflow.com/questions/linked/50251487?lq=1" target="_blank" title="https://stackoverflow.com/questions/linked/50251487?lq=1">24 questions linked to/from What are non-lexical lifetimes?</a>, which is a rough count of "solved by NLL" questions that I've touched in the last ~1.5 month</p>



<a name="128615122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128615122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128615122">(Jun 25 2018 at 18:27)</a>:</h4>
<blockquote>
<p>Thought experiment: does the MIR-based borrowck remove the need for (mutable?) reborrowing?</p>
</blockquote>
<p>I do not believe so. =) I mean when you do <code>let bar: &amp;mut X; foo(bar)</code>, you still don't want to <em>move</em> <code>bar</code> -- that requires reborrowing</p>



<a name="128615136"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128615136" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128615136">(Jun 25 2018 at 18:27)</a>:</h4>
<p>put another way, reborrowing occurs before MIR borrowck enters the picture (during MIR lowering)</p>



<a name="128616169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128616169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128616169">(Jun 25 2018 at 18:48)</a>:</h4>
<p>Yeah, that makes sense. Are there some cases where reborrowing is used to "trick" the borrow checker?</p>



<a name="128616260"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128616260" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128616260">(Jun 25 2018 at 18:50)</a>:</h4>
<p>The context was <a href="https://stackoverflow.com/q/51015503/155423" target="_blank" title="https://stackoverflow.com/q/51015503/155423">https://stackoverflow.com/q/51015503/155423</a> / <a href="https://stackoverflow.com/q/45095523/155423" target="_blank" title="https://stackoverflow.com/q/45095523/155423">https://stackoverflow.com/q/45095523/155423</a>, but I don't know why the OP actually needed the code in question</p>



<a name="128670420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128670420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128670420">(Jun 26 2018 at 18:07)</a>:</h4>
<p>do we already track this NLL ICE ? <a href="https://github.com/rust-lang/rust/issues/51348#issuecomment-400398622" target="_blank" title="https://github.com/rust-lang/rust/issues/51348#issuecomment-400398622">https://github.com/rust-lang/rust/issues/51348#issuecomment-400398622</a></p>



<a name="128671876"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671876" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671876">(Jun 26 2018 at 18:34)</a>:</h4>
<p>I'm not really aware of it</p>



<a name="128671884"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671884" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671884">(Jun 26 2018 at 18:34)</a>:</h4>
<p>one thing I wanted to do was to start paying more attention to ICEs and soundness bugs</p>



<a name="128671891"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671891" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671891">(Jun 26 2018 at 18:34)</a>:</h4>
<p>though I feel like performance + diagnostics are not <em>quite</em> there yet</p>



<a name="128671894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671894">(Jun 26 2018 at 18:35)</a>:</h4>
<p>but I'm worried about neglecting those categories too much :)</p>



<a name="128671915"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671915" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671915">(Jun 26 2018 at 18:35)</a>:</h4>
<p>agreed :) also why it's indeed a good idea to check bootstrapping + crater soon</p>



<a name="128671967"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671967" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671967">(Jun 26 2018 at 18:36)</a>:</h4>
<p>"are _not quite_ there yet" you mean ?</p>



<a name="128671969"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671969" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671969">(Jun 26 2018 at 18:36)</a>:</h4>
<p>yes :)</p>



<a name="128671975"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128671975" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128671975">(Jun 26 2018 at 18:36)</a>:</h4>
<p>:)</p>



<a name="128672500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128672500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128672500">(Jun 26 2018 at 18:45)</a>:</h4>
<p>nice, with the new issues, it looks like we can make some more performance progress soon as well</p>



<a name="128673614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128673614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128673614">(Jun 26 2018 at 19:05)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> re: <a href="https://github.com/rust-lang/rust/issues/51377#issuecomment-400420054" target="_blank" title="https://github.com/rust-lang/rust/issues/51377#issuecomment-400420054">https://github.com/rust-lang/rust/issues/51377#issuecomment-400420054</a> you mean we might need to reprofile again right ? (as #51411 has already landed)</p>



<a name="128752230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128752230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128752230">(Jun 28 2018 at 03:27)</a>:</h4>
<p><strong><em>Before</em></strong></p>
<div class="codehilite"><pre><span></span><span class="k">enum</span> <span class="nc">LastOrNot</span><span class="o">&lt;</span><span class="na">&#39;a</span><span class="o">&gt;</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">Last</span><span class="p">(</span><span class="o">&amp;</span><span class="na">&#39;a</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">Node</span><span class="p">),</span><span class="w"></span>
<span class="w">    </span><span class="n">NotLast</span><span class="p">(</span><span class="o">&amp;</span><span class="na">&#39;a</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">Node</span><span class="p">),</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">impl</span><span class="w"> </span><span class="n">Node</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">fn</span> <span class="nf">get_last_or_self</span><span class="p">(</span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="bp">self</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="nc">LastOrNot</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="k">match</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">children</span><span class="p">.</span><span class="n">is_empty</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="kc">false</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="n">LastOrNot</span>::<span class="n">Last</span><span class="p">(</span><span class="bp">self</span><span class="p">.</span><span class="n">children</span><span class="p">.</span><span class="n">last_mut</span><span class="p">().</span><span class="n">unwrap</span><span class="p">()),</span><span class="w"></span>
<span class="w">            </span><span class="kc">true</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="n">LastOrNot</span>::<span class="n">NotLast</span><span class="p">(</span><span class="bp">self</span><span class="p">),</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">get_last</span><span class="p">(</span><span class="k">mut</span><span class="w"> </span><span class="n">current</span>: <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="n">Node</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="n">Node</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">loop</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="k">match</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">current</span><span class="w"> </span><span class="p">}.</span><span class="n">get_last_or_self</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="n">LastOrNot</span>::<span class="n">Last</span><span class="p">(</span><span class="n">child</span><span class="p">)</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="n">current</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">child</span><span class="p">,</span><span class="w"></span>
<span class="w">            </span><span class="n">LastOrNot</span>::<span class="n">NotLast</span><span class="p">(</span><span class="n">end</span><span class="p">)</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">end</span><span class="p">,</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<p><strong>after</strong></p>
<div class="codehilite"><pre><span></span><span class="k">impl</span><span class="w"> </span><span class="n">Node</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">fn</span> <span class="nf">get_last</span><span class="p">(</span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="bp">self</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="nb">Option</span><span class="o">&lt;&amp;</span><span class="k">mut</span><span class="w"> </span><span class="n">Node</span><span class="o">&gt;</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="bp">self</span><span class="p">.</span><span class="n">children</span><span class="p">.</span><span class="n">last_mut</span><span class="p">()</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">get_last</span><span class="p">(</span><span class="k">mut</span><span class="w"> </span><span class="n">current</span>: <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="n">Node</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="n">Node</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="k">while</span><span class="w"> </span><span class="kd">let</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="n">child</span><span class="p">)</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">current</span><span class="p">.</span><span class="n">get_last</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="n">current</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">child</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="w">    </span><span class="n">current</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="128809452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128809452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128809452">(Jun 29 2018 at 03:59)</a>:</h4>
<p>NLL + Polonius win.</p>
<p>### Before</p>



<a name="128818901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128818901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128818901">(Jun 29 2018 at 09:15)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> ?</p>



<a name="128831242"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128831242" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128831242">(Jun 29 2018 at 14:33)</a>:</h4>
<p>howdy <span class="user-mention" data-user-id="116009">@nikomatsakis</span> </p>
<p>Amusingly, I was awake at 5:!5 AM my time, but not near a computer :-)</p>



<a name="128831271"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128831271" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128831271">(Jun 29 2018 at 14:33)</a>:</h4>
<p>I was confused because you wrote this:</p>
<div class="codehilite"><pre><span></span>NLL + Polonius win.

### Before
</pre></div>



<a name="128831274"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128831274" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128831274">(Jun 29 2018 at 14:33)</a>:</h4>
<p>but maybe it was just a mistake :)</p>



<a name="128831430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/128831430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#128831430">(Jun 29 2018 at 14:36)</a>:</h4>
<p>Huh. It <em>was</em> a mistake, but I sent <a href="#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128809452" title="#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128809452">https://rust-lang.zulipchat.com/#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128809452</a> <strong>before</strong> I sent <a href="#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128752230" title="#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128752230">https://rust-lang.zulipchat.com/#narrow/stream/122657-wg-nll/subject/general.20discussion/near/128752230</a></p>



<a name="129047874"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129047874" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129047874">(Jul 03 2018 at 21:08)</a>:</h4>
<p>I thought that using <code>#![feature(kjhadkjdjk)]</code> reported an error...</p>



<a name="129048077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048077">(Jul 03 2018 at 21:12)</a>:</h4>
<p>It <em>should</em></p>



<a name="129048187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048187">(Jul 03 2018 at 21:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> <a href="https://play.integer32.com/?gist=f903649f836e2b4dc3c0cf2e06dce93f&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.integer32.com/?gist=f903649f836e2b4dc3c0cf2e06dce93f&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.integer32.com/?gist=f903649f836e2b4dc3c0cf2e06dce93f&amp;version=nightly&amp;mode=debug&amp;edition=2015</a></p>



<a name="129048199"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048199" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048199">(Jul 03 2018 at 21:14)</a>:</h4>
<p>Am I doing a dumb-o somewhere?</p>



<a name="129048218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048218">(Jul 03 2018 at 21:15)</a>:</h4>
<p>Looks like a bug to me -- I'll go run a bisection</p>



<a name="129048226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048226">(Jul 03 2018 at 21:15)</a>:</h4>
<p>I think it's kinda' been that way for a while</p>



<a name="129048236"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048236" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048236">(Jul 03 2018 at 21:15)</a>:</h4>
<p>I feel like I noticed this a while back but thought "oh I must have remembered wrong"</p>



<a name="129048239"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048239" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048239">(Jul 03 2018 at 21:15)</a>:</h4>
<p>I could be mistaken though</p>



<a name="129048651"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048651" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048651">(Jul 03 2018 at 21:24)</a>:</h4>
<p>I was worried that I wasn't actually invoking NLL when trying to reduce that testcase, so I threw in some junk</p>



<a name="129048684"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048684" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048684">(Jul 03 2018 at 21:25)</a>:</h4>
<p>2017-08-11 prints a <em>warning</em> (unused or unknown feature)</p>



<a name="129048830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048830">(Jul 03 2018 at 21:28)</a>:</h4>
<p>2016-11-21 highlighted the feature name, not just the underline...</p>



<a name="129048913"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048913" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048913">(Jul 03 2018 at 21:30)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> Yeah, looks like this has ~never been a thing</p>



<a name="129048914"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048914" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048914">(Jul 03 2018 at 21:30)</a>:</h4>
<p>I must have remembered wrong</p>



<a name="129048952"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048952" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048952">(Jul 03 2018 at 21:31)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> what happened to the warning tho?</p>



<a name="129048965"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129048965" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129048965">(Jul 03 2018 at 21:31)</a>:</h4>
<p>hm, I did not attempt to bisect when it disappeared, let me do that</p>



<a name="129049074"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129049074" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129049074">(Jul 03 2018 at 21:33)</a>:</h4>
<p>I mean, I could see non-error as a case, sure, maybe....</p>



<a name="129049386"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129049386" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129049386">(Jul 03 2018 at 21:41)</a>:</h4>
<p>bisection claims 2017-09-09 is the first nightly that regressed, but I'm still trying to narrow down a specific commit</p>



<a name="129049451"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129049451" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129049451">(Jul 03 2018 at 21:43)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> I suspect <a href="https://github.com/rust-lang/rust/pull/44142" target="_blank" title="https://github.com/rust-lang/rust/pull/44142">https://github.com/rust-lang/rust/pull/44142</a> (the commit range if I'm reading it right is d93036a04 to dead08cb3).</p>



<a name="129058300"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129058300" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129058300">(Jul 04 2018 at 01:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> shall I file an issue?</p>



<a name="129058441"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129058441" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129058441">(Jul 04 2018 at 02:02)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> Probably, yeah, though not urgent of course</p>



<a name="129058489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129058489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129058489">(Jul 04 2018 at 02:04)</a>:</h4>
<p>Didn't we just tell everyone to go add <code>rust2018-preview</code> feature all over the place? :-)</p>



<a name="129059101"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129059101" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129059101">(Jul 04 2018 at 02:24)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> Sure, but technically they'll presumably notice if they get it wrong because things won't work</p>



<a name="129059108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129059108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129059108">(Jul 04 2018 at 02:25)</a>:</h4>
<p>This is <em>more urgent</em> because of that, though, yeah</p>



<a name="129151469"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151469" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151469">(Jul 05 2018 at 17:27)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> What's the best issue for me to take on next?</p>



<a name="129151700"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151700" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151700">(Jul 05 2018 at 17:31)</a>:</h4>
<p><span class="user-mention" data-user-id="116107">@David Wood</span> I'm skimming the list</p>



<a name="129151705"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151705" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151705">(Jul 05 2018 at 17:31)</a>:</h4>
<p>are you interested in doing some of the region follow-up?</p>



<a name="129151754"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151754" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151754">(Jul 05 2018 at 17:32)</a>:</h4>
<p>specifically, trying to improve the "naming" of regions and stuff like <a href="https://internals.rust-lang.org/t/presenting-lifetime-inference-errors-better-in-nll/7881/14?u=nikomatsakis" target="_blank" title="https://internals.rust-lang.org/t/presenting-lifetime-inference-errors-better-in-nll/7881/14?u=nikomatsakis">we talked about here</a>?</p>



<a name="129151759"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151759" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151759">(Jul 05 2018 at 17:32)</a>:</h4>
<p>I was hoping to open some issues with mild mentoring instructions in that area</p>



<a name="129151783"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151783" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151783">(Jul 05 2018 at 17:33)</a>:</h4>
<p>Yeah, that sounds good.</p>



<a name="129151792"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151792" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151792">(Jul 05 2018 at 17:33)</a>:</h4>
<p>hi <span class="user-mention" data-user-id="116009">@nikomatsakis</span></p>



<a name="129151803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151803">(Jul 05 2018 at 17:33)</a>:</h4>
<p>Hi <span class="user-mention" data-user-id="120823">@DPC</span> =)</p>



<a name="129151848"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151848" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151848">(Jul 05 2018 at 17:34)</a>:</h4>
<p><span class="user-mention" data-user-id="116107">@David Wood</span> are you ready to hack now or would it be later today?</p>



<a name="129151859"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151859" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151859">(Jul 05 2018 at 17:34)</a>:</h4>
<p>I can go now.</p>



<a name="129151866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151866">(Jul 05 2018 at 17:34)</a>:</h4>
<p>let's make a topic for that I guess</p>



<a name="129151887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151887">(Jul 05 2018 at 17:35)</a>:</h4>
<p><span class="user-mention" data-user-id="120823">@DPC</span> (how goes?)</p>



<a name="129151966"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129151966" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129151966">(Jul 05 2018 at 17:36)</a>:</h4>
<p>starting on the issue rn and i'm kinda lost after going through it earlier today <span class="emoji emoji-1f609" title="wink">:wink:</span></p>



<a name="129152077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129152077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129152077">(Jul 05 2018 at 17:37)</a>:</h4>
<p>cool, let me start a topic jsut for that to help keep the messages straight</p>



<a name="129152135"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129152135" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129152135">(Jul 05 2018 at 17:38)</a>:</h4>
<p>sure</p>



<a name="129202334"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202334" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202334">(Jul 06 2018 at 13:47)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> good luck <span class="emoji emoji-1f1eb-1f1f7" title="fr">:fr:</span></p>



<a name="129202405"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202405" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202405">(Jul 06 2018 at 13:48)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> haha good luck to you as well :)</p>



<a name="129202421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202421">(Jul 06 2018 at 13:48)</a>:</h4>
<p>:)</p>



<a name="129202434"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202434" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202434">(Jul 06 2018 at 13:49)</a>:</h4>
<p>I'm extremely nervous :P</p>



<a name="129202447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202447">(Jul 06 2018 at 13:49)</a>:</h4>
<p>because of Cavani ?</p>



<a name="129202455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202455">(Jul 06 2018 at 13:49)</a>:</h4>
<p>no no, because of the match in general</p>



<a name="129202458"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202458" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202458">(Jul 06 2018 at 13:49)</a>:</h4>
<p>:)</p>



<a name="129202499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202499">(Jul 06 2018 at 13:50)</a>:</h4>
<p>feels like it will be tough in general for both sides :)</p>



<a name="129202528"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202528" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202528">(Jul 06 2018 at 13:50)</a>:</h4>
<p>yeah. but without Cavani, Uruguay will find it tough</p>



<a name="129202530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202530">(Jul 06 2018 at 13:50)</a>:</h4>
<p>I'm not sure how people in France live this kind of matches, but here is complete craziness</p>



<a name="129202537"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202537" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202537">(Jul 06 2018 at 13:50)</a>:</h4>
<p>people don't work</p>



<a name="129202539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202539">(Jul 06 2018 at 13:50)</a>:</h4>
<p>offices close</p>



<a name="129202543"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202543" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202543">(Jul 06 2018 at 13:50)</a>:</h4>
<p>etc, etc</p>



<a name="129202561"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202561" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202561">(Jul 06 2018 at 13:51)</a>:</h4>
<p>that's crazy</p>



<a name="129202565"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202565" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202565">(Jul 06 2018 at 13:51)</a>:</h4>
<blockquote>
<p>yeah. but without Cavani, Uruguay will find it tough</p>
</blockquote>
<p>yes, without Cavani is harder</p>



<a name="129202580"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202580" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202580">(Jul 06 2018 at 13:51)</a>:</h4>
<blockquote>
<p>that's crazy</p>
</blockquote>
<p>football in south america is a hard to understand passion</p>



<a name="129202586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202586">(Jul 06 2018 at 13:51)</a>:</h4>
<p>offices don't close per se, but a lot of people watch the game instead of working</p>



<a name="129202587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202587">(Jul 06 2018 at 13:51)</a>:</h4>
<p><span class="user-mention" data-user-id="120823">@DPC</span> where are you from?</p>



<a name="129202589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202589">(Jul 06 2018 at 13:51)</a>:</h4>
<p>India</p>



<a name="129202643"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202643" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202643">(Jul 06 2018 at 13:52)</a>:</h4>
<p>but yeah, at 1/4 finals people are getting passionate</p>



<a name="129202655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202655">(Jul 06 2018 at 13:52)</a>:</h4>
<p>yeah</p>



<a name="129202667"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202667" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202667">(Jul 06 2018 at 13:53)</a>:</h4>
<p>here there's no man that haven't played football at some point of his life</p>



<a name="129202672"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202672" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202672">(Jul 06 2018 at 13:53)</a>:</h4>
<p>and woman are starting more and more to play also</p>



<a name="129202677"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202677" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202677">(Jul 06 2018 at 13:53)</a>:</h4>
<p>that's why such a small country more or less does well in the sport :)</p>



<a name="129202680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202680">(Jul 06 2018 at 13:53)</a>:</h4>
<p>3 million people lives here</p>



<a name="129202733"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202733" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202733">(Jul 06 2018 at 13:54)</a>:</h4>
<p>and we have won 2 world cups and 15 south american cups (even more than Brazil and Argentina)</p>



<a name="129202756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202756">(Jul 06 2018 at 13:54)</a>:</h4>
<p>the city where I work has a bigger population than that</p>



<a name="129202769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202769">(Jul 06 2018 at 13:55)</a>:</h4>
<p>yes :)</p>



<a name="129202786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202786">(Jul 06 2018 at 13:55)</a>:</h4>
<p>and 2 olympics which technically count as 2 world cups ;)</p>



<a name="129202793"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202793" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202793">(Jul 06 2018 at 13:55)</a>:</h4>
<p>yes</p>



<a name="129202794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202794">(Jul 06 2018 at 13:55)</a>:</h4>
<p><a href="https://en.wikipedia.org/wiki/Copa_Am%C3%A9rica#Performance_by_country" target="_blank" title="https://en.wikipedia.org/wiki/Copa_Am%C3%A9rica#Performance_by_country">https://en.wikipedia.org/wiki/Copa_Am%C3%A9rica#Performance_by_country</a></p>



<a name="129202803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202803">(Jul 06 2018 at 13:55)</a>:</h4>
<p>we have won 15 and Brazil only 8 ;)</p>



<a name="129202836"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202836" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202836">(Jul 06 2018 at 13:56)</a>:</h4>
<p>anyway, best of luck to you</p>



<a name="129202855"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202855" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202855">(Jul 06 2018 at 13:56)</a>:</h4>
<p>leaving this because the game is starting</p>



<a name="129202857"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202857" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202857">(Jul 06 2018 at 13:56)</a>:</h4>
<p>:)</p>



<a name="129202859"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129202859" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129202859">(Jul 06 2018 at 13:56)</a>:</h4>
<p>same here, everyone is stopping work lol</p>



<a name="129210127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210127">(Jul 06 2018 at 16:06)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> congrats again, France played fantastic and Uruguay a bit bad :(</p>



<a name="129210338"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210338" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210338">(Jul 06 2018 at 16:11)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> you too, Cavani missing was very unfortunate :/ Uruguay deserved better, as they were very very good</p>



<a name="129210366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210366">(Jul 06 2018 at 16:12)</a>:</h4>
<p>I think we would have lost with Cavani and also with a bit of better luck</p>



<a name="129210414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210414">(Jul 06 2018 at 16:12)</a>:</h4>
<p>I think France would have won anyway, but still here we are sad that in all the world cups we always miss the best player for key matches</p>



<a name="129210430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210430">(Jul 06 2018 at 16:13)</a>:</h4>
<p>definitely bad luck :/</p>



<a name="129210433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210433">(Jul 06 2018 at 16:13)</a>:</h4>
<p>I wanted to lose with all the team, that's the sad part but ... :/</p>



<a name="129210451"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210451" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210451">(Jul 06 2018 at 16:13)</a>:</h4>
<p>I will be supporting Uruguay in the future now that I know you :D</p>



<a name="129210604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129210604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129210604">(Jul 06 2018 at 16:16)</a>:</h4>
<p>:D <span class="emoji emoji-2764" title="heart">:heart:</span></p>



<a name="129213569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129213569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129213569">(Jul 06 2018 at 17:15)</a>:</h4>
<p>congrats <span class="user-mention" data-user-id="116113">@lqd</span></p>



<a name="129213590"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129213590" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129213590">(Jul 06 2018 at 17:15)</a>:</h4>
<p>:)</p>



<a name="129371845"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129371845" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129371845">(Jul 09 2018 at 20:30)</a>:</h4>
<p>I really hope y'all pull off a miracle and get Polonius as part of Rust 2018</p>



<a name="129372007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372007">(Jul 09 2018 at 20:32)</a>:</h4>
<p>why in particular ? (it seems very unlikely right?)</p>



<a name="129372192"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372192" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372192">(Jul 09 2018 at 20:35)</a>:</h4>
<p>I don't have as good of a sense of likely/unlikely as you do, but the reason is that I don't know that "the public" is going to care about the fine grained distinction that we know of.</p>



<a name="129372219"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372219" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372219">(Jul 09 2018 at 20:35)</a>:</h4>
<p>I sense that NLL is thought of as "the thing that will make the borrow checker not reject valid programs"</p>



<a name="129372280"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372280" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372280">(Jul 09 2018 at 20:36)</a>:</h4>
<p>oh, and Polonius would match that goal better presumably</p>



<a name="129372310"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372310" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372310">(Jul 09 2018 at 20:37)</a>:</h4>
<p>Right, because of NLL case <a href="https://github.com/rust-lang/rust/issues/3" target="_blank" title="https://github.com/rust-lang/rust/issues/3">#3</a>, conditionals</p>



<a name="129372358"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372358" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372358">(Jul 09 2018 at 20:38)</a>:</h4>
<p>maybe explaining it as a series of steps towards that goal of accepting more and more versions of "all" valid programs ?</p>



<a name="129372470"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372470" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372470">(Jul 09 2018 at 20:40)</a>:</h4>
<p>Perhaps, but it's tied up with this idea of the edition. What's "the point" of the edition if it only halfway implements NLL? ( I mean, I know there's a point, but for argument's sake )</p>



<a name="129372489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372489">(Jul 09 2018 at 20:41)</a>:</h4>
<p>I also heard that async / await may not ship with the edition, just the keyword reservations. That seems likewise unfortunate.</p>



<a name="129372498"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372498" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372498">(Jul 09 2018 at 20:41)</a>:</h4>
<p>That's hearsay and gossip ^ so it could easily be wrong.</p>



<a name="129372557"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372557" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372557">(Jul 09 2018 at 20:42)</a>:</h4>
<p>yeah, even though (and I could be wrong) I feel like the transition from AST borrowck to NLL is bigger than NLL to NLL 2.0/Polonius</p>



<a name="129372710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372710">(Jul 09 2018 at 20:45)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> since you have a lot of experience with real world code and SO questions, do you think NLLs without Polonius would still be a "gamechanger" for the cases you encountered ?</p>



<a name="129372780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372780">(Jul 09 2018 at 20:46)</a>:</h4>
<p>These are the questions I've linked to the "what is NLL" question - <a href="https://stackoverflow.com/questions/linked/50251487?lq=1" target="_blank" title="https://stackoverflow.com/questions/linked/50251487?lq=1">https://stackoverflow.com/questions/linked/50251487?lq=1</a></p>



<a name="129372798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372798">(Jul 09 2018 at 20:46)</a>:</h4>
<p>I think many of them will be improved with current NLL</p>



<a name="129372819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372819">(Jul 09 2018 at 20:47)</a>:</h4>
<p>But just a few minutes ago I had to say "that's not the real NLL" (referring to today's implementation)</p>



<a name="129372833"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372833" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372833">(Jul 09 2018 at 20:47)</a>:</h4>
<p>what was the code in question ?</p>



<a name="129372901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372901">(Jul 09 2018 at 20:49)</a>:</h4>
<p><a href="https://play.rust-lang.org/?gist=bee131949c07b68cbae7f0ba67fc4cf6&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=bee131949c07b68cbae7f0ba67fc4cf6&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.rust-lang.org/?gist=bee131949c07b68cbae7f0ba67fc4cf6&amp;version=nightly&amp;mode=debug&amp;edition=2015</a></p>



<a name="129372924"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129372924" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129372924">(Jul 09 2018 at 20:49)</a>:</h4>
<p>dayum</p>



<a name="129373031"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129373031" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129373031">(Jul 09 2018 at 20:51)</a>:</h4>
<p>:/</p>



<a name="129373035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129373035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129373035">(Jul 09 2018 at 20:51)</a>:</h4>
<p>There's also the more complicated <a href="https://stackoverflow.com/questions/50519147/double-mutable-borrow-error-in-a-loop-happens-even-with-nll-on" target="_blank" title="https://stackoverflow.com/questions/50519147/double-mutable-borrow-error-in-a-loop-happens-even-with-nll-on">https://stackoverflow.com/questions/50519147/double-mutable-borrow-error-in-a-loop-happens-even-with-nll-on</a></p>



<a name="129373241"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129373241" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129373241">(Jul 09 2018 at 20:55)</a>:</h4>
<p>I liked your good news / bad news here</p>



<a name="129373372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129373372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129373372">(Jul 09 2018 at 20:57)</a>:</h4>
<p>I think the edition cutoff is like in a month and a half (and a bit)</p>



<a name="129373886"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129373886" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129373886">(Jul 09 2018 at 21:06)</a>:</h4>
<p>Yeah, I try to give some hope to people when I tell them things they won't like <span class="emoji emoji-1f609" title="wink">:wink:</span></p>



<a name="129406532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129406532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129406532">(Jul 10 2018 at 11:42)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> one reason why its worth tying even a "halfway-done" version of NLL to the edition: NLL changes the semantics for how pattern variables work in match guards</p>



<a name="129406552"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129406552" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129406552">(Jul 10 2018 at 11:44)</a>:</h4>
<p>it does so in a way that is meant to fly under the (developer's) radar in most cases, and it is fixing a soundness bug, but it is a change to the semantics nonetheless (and not solely making more programs pass the borrow-checker)</p>



<a name="129409688"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129409688" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129409688">(Jul 10 2018 at 12:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> oh, I should strive to be more clear. I do think that it's good to have them tied together, I just wish it was NLL to the max</p>



<a name="129409741"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129409741" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129409741">(Jul 10 2018 at 12:56)</a>:</h4>
<p>Really, it's more of a "I wish the edition could just be delayed a bit to fully deliver all these things together"</p>



<a name="129428578"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428578" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428578">(Jul 10 2018 at 19:12)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> are we having the meeting today?</p>



<a name="129428589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428589">(Jul 10 2018 at 19:13)</a>:</h4>
<p>yes i am planning to do so</p>



<a name="129428593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428593">(Jul 10 2018 at 19:13)</a>:</h4>
<p>given that Niko is not around and France is playing semis, I see this ... ahh ok ok :)</p>



<a name="129428594"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428594" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428594">(Jul 10 2018 at 19:13)</a>:</h4>
<p>in 17 minutes, right?</p>



<a name="129428600"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428600" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428600">(Jul 10 2018 at 19:13)</a>:</h4>
<p>yes</p>



<a name="129428604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428604">(Jul 10 2018 at 19:13)</a>:</h4>
<p>i'm not watching the game, though I am definitely hearing the results as they happen</p>



<a name="129428653"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428653" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428653">(Jul 10 2018 at 19:14)</a>:</h4>
<p><span class="emoji emoji-1f44d" title="+1">:+1:</span></p>



<a name="129428654"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428654" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428654">(Jul 10 2018 at 19:14)</a>:</h4>
<p>1-0 <span class="emoji emoji-1f1eb-1f1f7" title="fr">:fr:</span>  ;) I'll be watching the game during the meeting :p (but participating ofc)</p>



<a name="129428676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428676">(Jul 10 2018 at 19:15)</a>:</h4>
<p>btw I've added my status update to the Paper</p>



<a name="129428738"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428738" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428738">(Jul 10 2018 at 19:16)</a>:</h4>
<p>my bet was <span class="emoji emoji-1f1eb-1f1f7" title="fr">:fr:</span> 2 belgium 1</p>



<a name="129428756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129428756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129428756">(Jul 10 2018 at 19:17)</a>:</h4>
<p>if we do such a thing as nominated issues there's an ICE in the just released 1.27.1 <a href="https://github.com/rust-lang/rust/issues/52213" target="_blank" title="https://github.com/rust-lang/rust/issues/52213">https://github.com/rust-lang/rust/issues/52213</a></p>



<a name="129429046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429046">(Jul 10 2018 at 19:23)</a>:</h4>
<blockquote>
<p>Really, it's more of a "I wish the edition could just be delayed a bit to fully deliver all these things together"</p>
</blockquote>
<p>My understanding of editions is that if the feature gets added after the 'edition' ships, and all the documentation is updated to reflect the change, then it will be like the feature shipped with the edition? Or will NLL 2.0 change things to have to wait until the next edition?</p>



<a name="129429209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429209">(Jul 10 2018 at 19:27)</a>:</h4>
<p><span class="user-mention" data-user-id="121163">@Niel</span> my interpretation of <span class="user-mention" data-user-id="116155">@Jake Goulding</span> 's remarks is that they were more about getting the best initial marketing/word-of-mouth for the initial deployment of NLL. (perhaps thinking that People may not care to stick around to see if NLL 2.0 is ever successfully deployed?)</p>



<a name="129429323"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429323" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429323">(Jul 10 2018 at 19:29)</a>:</h4>
<p>Yep, mostly around the marketing aspect of it. Right now, we <em>could</em> just ship the edition with the keyword reservations and then deliver all the new functionality every 6 weeks, as usual.</p>



<a name="129429385"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429385" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429385">(Jul 10 2018 at 19:30)</a>:</h4>
<p>@lqd I'm not sure that's an NLL regression... or rather ... did you link to the bug you meant to? That's not describing an ICE, but rather than outright soundness bug?</p>



<a name="129429420"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429420" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429420">(Jul 10 2018 at 19:31)</a>:</h4>
<p>Hmmm, my understanding of marketing is that it takes several months to filter through the ranks. Any semantics/keywords should be in place for NLL 2.0 though.</p>



<a name="129429435"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429435" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429435">(Jul 10 2018 at 19:31)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I guess yeah, it's about AST borrowck and match default bindings, I was thinking maybe you would know your way around this in niko's absence</p>



<a name="129429510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429510">(Jul 10 2018 at 19:32)</a>:</h4>
<p>err wait not an ICE a segfault true</p>



<a name="129429552"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429552" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429552">(Jul 10 2018 at 19:33)</a>:</h4>
<p>(and also a segfault that is only exposed by AST borrowck if I read that correctly. Its something the compiler team needs to fix, perhaps <em>I</em> need to fix, but its not necessarily something that needs this groups' eyeballs)</p>



<a name="129429602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129429602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129429602">(Jul 10 2018 at 19:34)</a>:</h4>
<p>sure, I mostly wanted to bring your attention to it as people pinged you on discord and we were about to have the meeting :)</p>



<a name="129487985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129487985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129487985">(Jul 11 2018 at 18:03)</a>:</h4>
<p>to reset my mind from the triaging, I've made another couple of tiny polonius/<span class="emoji emoji-1f438" title="frog">:frog:</span> PRs :)</p>



<a name="129490912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129490912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129490912">(Jul 11 2018 at 18:51)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span>  What's triaging? I've looked through the HackMD page, but can't seem to determine what exactly the purpose of the document is?</p>



<a name="129491110"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491110" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491110">(Jul 11 2018 at 18:55)</a>:</h4>
<p>in this case it's looking at the crater run results, to decide if the errors they contain are a problem in the MIR borrowck or in the crate being tested, or if the diagnostics need work, and so on. The hackmd pages list some of these errors, with sometimes, explanations I've done, minimization of problems, or links to already known issues if the problems are indeed already filed</p>



<a name="129491239"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491239" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491239">(Jul 11 2018 at 18:57)</a>:</h4>
<p>Interesting, sounds like repetitive work. Also perhaps a good starting point for a rustacean-shrimp?</p>



<a name="129491309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491309">(Jul 11 2018 at 18:58)</a>:</h4>
<p>possibly yeah, depending on the cases, sometimes it's easy to minimize</p>



<a name="129491429"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491429" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491429">(Jul 11 2018 at 19:00)</a>:</h4>
<p>Oki. Show me tomorrow?</p>



<a name="129491526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491526">(Jul 11 2018 at 19:03)</a>:</h4>
<p>feel free to ask questions :) (but I'll be at work and not extremely available)</p>



<a name="129491697"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491697" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491697">(Jul 11 2018 at 19:06)</a>:</h4>
<p>(that way I can answer async)</p>



<a name="129491819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129491819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Niel <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129491819">(Jul 11 2018 at 19:08)</a>:</h4>
<p><span class="emoji emoji-1f44d" title="thumbs up">:thumbs_up:</span></p>



<a name="129492269"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129492269" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129492269">(Jul 11 2018 at 19:15)</a>:</h4>
<p>let me know if you need a hand <span class="emoji emoji-270b" title="hand">:hand:</span> :)</p>



<a name="129492344"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129492344" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129492344">(Jul 11 2018 at 19:17)</a>:</h4>
<p>oh but all help is very welcome for sure!</p>



<a name="129492411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129492411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129492411">(Jul 11 2018 at 19:18)</a>:</h4>
<p>eg every crate in <a href="https://hackmd.io/2sR4vloZQhC8arJkFOFyLA?both" target="_blank" title="https://hackmd.io/2sR4vloZQhC8arJkFOFyLA?both">https://hackmd.io/2sR4vloZQhC8arJkFOFyLA?both</a> which doesn't have a "-&gt;" with an explanation is one that can be triaged :)</p>



<a name="129527600"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129527600" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129527600">(Jul 12 2018 at 10:09)</a>:</h4>
<p>I was being silly and with Frank's help I completed the <code>LocationInsensitive</code> <em>leapfrog</em> variant. If you combine with yesterday's PRs, on <code>clap</code> (a great case for us as it <em>passes</em> the location insensitive analysis), yesterday's best run (unstable sort, redundant indexing, no leapfrog) was 800ms to today's best of 125ms. (caveats about microbenchmarking, mistakes on my part, lack of testing, etc)</p>



<a name="129535183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129535183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129535183">(Jul 12 2018 at 13:18)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> so it takes 15% of the time it used to? not bad!</p>



<a name="129535250"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129535250" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129535250">(Jul 12 2018 at 13:20)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> hopefully it is also, you know, ... correct <em>whistles</em></p>



<a name="129535960"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129535960" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129535960">(Jul 12 2018 at 13:34)</a>:</h4>
<p>Ain't y'all get tests in there yet?</p>



<a name="129536088"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129536088" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129536088">(Jul 12 2018 at 13:38)</a>:</h4>
<p>there are some, this variant has <em>one</em> test ;)</p>



<a name="129604240"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129604240" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129604240">(Jul 13 2018 at 14:35)</a>:</h4>
<p>Today in Polonius™ - results on the clap benchmark: -20% in the <code>datafrogopt</code> variant, and -15% in <code>leapfrog</code> (caveat: don't forget that these "optimized" variants still have known bugs and probably unknown ones ;)</p>



<a name="129616363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129616363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129616363">(Jul 13 2018 at 17:53)</a>:</h4>
<blockquote>
<p>error[E0499]: cannot borrow <code>*self</code> as mutable more than once at a time<br>
note: borrowed value must be valid for the lifetime 'a as defined on the impl at 8:1...</p>
</blockquote>



<a name="129616378"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129616378" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129616378">(Jul 13 2018 at 17:53)</a>:</h4>
<p>Why does that note belong with that error?</p>



<a name="129699019"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129699019" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129699019">(Jul 15 2018 at 11:45)</a>:</h4>
<p>Did this ever work with NLL/mir borrowck? I thought I've tried it before, but I can't find a past nightly where it did</p>
<div class="codehilite"><pre><span></span><span class="k">fn</span> <span class="nf">foo</span><span class="p">(</span><span class="n">x</span>: <span class="nb">Box</span><span class="o">&lt;&amp;</span><span class="k">mut</span><span class="w"> </span><span class="kt">i32</span><span class="o">&gt;</span><span class="p">)</span><span class="w"> </span>-&gt; <span class="kp">&amp;</span><span class="nc">mut</span><span class="w"> </span><span class="kt">i32</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="o">*</span><span class="n">x</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="129700540"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129700540" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129700540">(Jul 15 2018 at 12:39)</a>:</h4>
<p>It seems that <a href="https://github.com/rust-lang/rust/issues/45696" target="_blank" title="https://github.com/rust-lang/rust/issues/45696">https://github.com/rust-lang/rust/issues/45696</a> was closed, but the PR to fix it didn't actually fix it.</p>



<a name="129709048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129709048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129709048">(Jul 15 2018 at 16:56)</a>:</h4>
<p>Reopened <a href="https://github.com/rust-lang/rust/issues/45696" target="_blank" title="https://github.com/rust-lang/rust/issues/45696">https://github.com/rust-lang/rust/issues/45696</a></p>



<a name="129810307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129810307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129810307">(Jul 17 2018 at 12:38)</a>:</h4>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> BTW PR <a href="https://github.com/rust-lang/rust/issues/52405" target="_blank" title="https://github.com/rust-lang/rust/issues/52405">#52405</a> is an epic win</p>



<a name="129810377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129810377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129810377">(Jul 17 2018 at 12:40)</a>:</h4>
<p>the <em>only</em> nitpicky question I have is whether the test file <code>mutability-errors.rs</code> should be broken up into multiple files.</p>



<a name="129810422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129810422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129810422">(Jul 17 2018 at 12:40)</a>:</h4>
<p>but at this point I'm tempted to just r+ it as is.</p>



<a name="129810575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129810575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129810575">(Jul 17 2018 at 12:44)</a>:</h4>
<p>ah but it has merge conflicts anyway, so I'll go ahead and make my nitpicky comment</p>



<a name="129811021"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129811021" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129811021">(Jul 17 2018 at 12:55)</a>:</h4>
<p>wow, I was just skimming the tests. very nice indeed <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> <span class="emoji emoji-1f389" title="tada">:tada:</span></p>



<a name="129866365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129866365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129866365">(Jul 18 2018 at 11:35)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> easy r?s :) -- <a href="https://github.com/rust-lang-nursery/polonius/pull/72" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/72">https://github.com/rust-lang-nursery/polonius/pull/72</a> <a href="https://github.com/rust-lang-nursery/datafrog/pull/9" target="_blank" title="https://github.com/rust-lang-nursery/datafrog/pull/9">https://github.com/rust-lang-nursery/datafrog/pull/9</a></p>



<a name="129866794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129866794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129866794">(Jul 18 2018 at 11:43)</a>:</h4>
<p>thanks <span class="emoji emoji-2764" title="heart">:heart:</span></p>



<a name="129866880"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129866880" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129866880">(Jul 18 2018 at 11:44)</a>:</h4>
<p>(I'll space the others out during the next 10 years)</p>



<a name="129867011"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129867011" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129867011">(Jul 18 2018 at 11:47)</a>:</h4>
<p>(as a summary of the many things in-flight, leapfrog + compressed cfg + etc clocks in at around 1.5s)</p>



<a name="129868148"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129868148" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129868148">(Jul 18 2018 at 12:15)</a>:</h4>
<p>( for the live loans)</p>



<a name="129872622"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129872622" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129872622">(Jul 18 2018 at 13:51)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> can you remind us what thats in comparison to?</p>



<a name="129873273"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129873273" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129873273">(Jul 18 2018 at 14:02)</a>:</h4>
<p>suffering from a million branches, but from memory the <code>naive</code> (but correct) variant is at 30s; <code>datafrogopt</code> 5-6s</p>



<a name="129896187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129896187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129896187">(Jul 18 2018 at 21:09)</a>:</h4>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> informs me that </p>
<blockquote>
<p><code>-Zpolonius</code> is completely broken atm: it doesn't report any errors.</p>
</blockquote>
<p>I'd selfishly like to ask that be "fixed" either by disabling the flag or reporting the errors ;-)</p>



<a name="129896220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129896220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129896220">(Jul 18 2018 at 21:09)</a>:</h4>
<p>Because I've been using that to "prove" that some given piece of code will or won't work in the future</p>



<a name="129954786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954786">(Jul 19 2018 at 20:35)</a>:</h4>
<p>I used to pass <code>--stage 1 --keep-stage 0</code> to make building faster, that stopped working a while ago, what's the equivalent now? - I miss building quickly.</p>



<a name="129954865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954865">(Jul 19 2018 at 20:37)</a>:</h4>
<p>I use <code>./x.py build --stage 1 -i --keep-stage 1</code> and it seems to work pretty well</p>



<a name="129954878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954878">(Jul 19 2018 at 20:37)</a>:</h4>
<p>I don't really understand what the argument to <code>keep-stage</code> represents though :)</p>



<a name="129954887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954887">(Jul 19 2018 at 20:37)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> would know</p>



<a name="129954889"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954889" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954889">(Jul 19 2018 at 20:37)</a>:</h4>
<p>It's somewhat unclear to everyone :)</p>



<a name="129954944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954944">(Jul 19 2018 at 20:38)</a>:</h4>
<p>I thought it meant "don't bother rebuilding that, re-use it", so each time I'd just rebuild stage 1 (and then the <code>--stage 1</code> was slightly redundant).</p>



<a name="129954953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129954953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129954953">(Jul 19 2018 at 20:38)</a>:</h4>
<p>You probably want --keep-stage 0 without any --stage flag and then use stage2/bin/rustc</p>



<a name="129955065"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129955065" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129955065">(Jul 19 2018 at 20:40)</a>:</h4>
<p>I assume with that it would be safe to ignore the "warning: using potentially old..." messages?</p>



<a name="129955115"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129955115" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129955115">(Jul 19 2018 at 20:41)</a>:</h4>
<p>probably worth updating <a href="https://forge.rust-lang.org/x-py.html#other-flags" target="_blank" title="https://forge.rust-lang.org/x-py.html#other-flags">this part of the forge</a> which still mentions the old flags, that's where I got them from initially.</p>



<a name="129955452"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129955452" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129955452">(Jul 19 2018 at 20:46)</a>:</h4>
<p>It's generally safe to ignore yes, certainly for (most) NLL work</p>



<a name="129992563"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129992563" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129992563">(Jul 20 2018 at 12:02)</a>:</h4>
<p>If I <code>x.py build</code> first without <code>-keep-stage</code> or <code>--stage</code> and then in subsequent builds use only <code>-keep-stage 0</code> then it works as expected. It seems though that if I switch to using <code>x.py check</code> (still with <code>--keep-stage 0</code>) then any subsequent <code>x.py build</code>s with <code>--keep-stage 0</code> will fail unless I do a full build without <code>--keep-stage 0</code> again. Is that intended?</p>



<a name="129995112"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129995112" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129995112">(Jul 20 2018 at 12:56)</a>:</h4>
<p>No -- I think eddyb also mentioned that. If you could file an issue with that description that'd be great</p>



<a name="129995273"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129995273" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129995273">(Jul 20 2018 at 12:59)</a>:</h4>
<p><span class="user-mention" data-user-id="116122">@simulacrum</span> <a href="https://github.com/rust-lang/rust/issues/52565" target="_blank" title="https://github.com/rust-lang/rust/issues/52565">#52565</a></p>



<a name="129995332"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/129995332" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#129995332">(Jul 20 2018 at 13:00)</a>:</h4>
<p>Thanks!</p>



<a name="130069018"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130069018" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130069018">(Jul 21 2018 at 20:37)</a>:</h4>
<p>Could someone r+ <a href="https://github.com/rust-lang/rust/pull/52359" target="_blank" title="https://github.com/rust-lang/rust/pull/52359">https://github.com/rust-lang/rust/pull/52359</a>, please?</p>



<a name="130069174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130069174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130069174">(Jul 21 2018 at 20:41)</a>:</h4>
<p>Done</p>



<a name="130210150"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210150" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210150">(Jul 24 2018 at 13:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> is there any plan to make the <code>region</code> concept transparent or more friendly to ordinary users in nll error message?  lifetime is used in most error message, but some of them use <code>region</code>, and lifetime is more common in teaching Rust. for example: </p>
<div class="codehilite"><pre><span></span>  --&gt; $DIR/return-wrong-bound-region.rs:21:23
   |
LL |     expect_sig(|a, b| b); // ought to return `a`
   |                 -  -  ^ free region requires that `&#39;1` must outlive `&#39;2`
   |                 |  |
   |                 |  lifetime `&#39;1` appears in this argument
   |                 lifetime `&#39;2` appears in this argument
</pre></div>



<a name="130210169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210169">(Jul 24 2018 at 13:16)</a>:</h4>
<p>I don't believe the "free region requires" is meant to be part of the message long term</p>



<a name="130210179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210179">(Jul 24 2018 at 13:17)</a>:</h4>
<p>I would prefer not to use the word lifetime, which I think is quite confusing for people</p>



<a name="130210184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210184">(Jul 24 2018 at 13:17)</a>:</h4>
<p>but I haven't found a good alternative...</p>



<a name="130210297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210297">(Jul 24 2018 at 13:19)</a>:</h4>
<p>in any case I would expect that message to say something like "returning <code>b</code> requires that <code>'2</code> outlives <code>'1</code>"</p>



<a name="130210413"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130210413" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130210413">(Jul 24 2018 at 13:21)</a>:</h4>
<p><span class="user-mention" data-user-id="116773">@csmoe</span> <span class="user-mention" data-user-id="116009">@nikomatsakis</span> It says the following with <a href="https://github.com/rust-lang/rust/issues/52648" target="_blank" title="https://github.com/rust-lang/rust/issues/52648">#52648</a>:</p>
<div class="codehilite"><pre><span></span>error: unsatisfied lifetime constraints
  --&gt; $DIR/return-wrong-bound-region.rs:21:23
   |
LL |     expect_sig(|a, b| b); // ought to return `a`
   |                 -  -  ^ closure was supposed to return data with lifetime `&#39;1` but it is returning data with lifetime `&#39;2`
   |                 |  |
   |                 |  has type `&amp;&#39;1 i32`
   |                 | has type `&amp;&#39;2 i32`
</pre></div>



<a name="130234659"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130234659" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130234659">(Jul 24 2018 at 20:23)</a>:</h4>
<blockquote>
<p>I would prefer not to use the word lifetime, which I think is quite confusing for people</p>
</blockquote>
<p>I brought this up on <em>some</em> RFC, but I think that abandoning "lifetime" 3 years after Rust 1.0 isn't something we should do, and <em>definitely</em> not something that should be done without an RFC. Getting rid of that word (even though I agree it wasn't the best choice) would undo <em>many</em> years of documentation and so on.</p>



<a name="130235026"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235026" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235026">(Jul 24 2018 at 20:29)</a>:</h4>
<p>I don't disagree, though I do think that if we can find better ways to explain things, we should.</p>



<a name="130235039"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235039" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235039">(Jul 24 2018 at 20:29)</a>:</h4>
<p>that is, I'm not proposing a kind of "hard" deprecation -- in fact, i'm not really proposed a deprecation at all, since most of our messages are using the word lifetime right now</p>



<a name="130235045"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235045" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235045">(Jul 24 2018 at 20:29)</a>:</h4>
<p>but if we can find ways to express what we need that avoid the term, better still</p>



<a name="130235103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235103">(Jul 24 2018 at 20:30)</a>:</h4>
<p>that said I pretty commonly hear people getting confused about the lifetime of the <em>underlying value</em> and that of the reference itself</p>



<a name="130235254"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235254" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235254">(Jul 24 2018 at 20:32)</a>:</h4>
<p>Absolutely. Lifetimes in Rust means "time at a specific memory address". Some people are accustomed to thinking of it as "time from construction to destruction"</p>



<a name="130235296"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235296" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235296">(Jul 24 2018 at 20:33)</a>:</h4>
<p>Semi-related: I keep seeing <code>'1</code> in the errors. What's that about?</p>



<a name="130235306"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235306">(Jul 24 2018 at 20:33)</a>:</h4>
<p>is that a test placeholder thing?</p>



<a name="130235405"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235405" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235405">(Jul 24 2018 at 20:34)</a>:</h4>
<p>the idea is to give a name to the lifetime in question so we can talk about it later -- particularly anonymous ones</p>



<a name="130235425"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235425" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235425">(Jul 24 2018 at 20:35)</a>:</h4>
<p>unclear to me still if calling it with some untypable name is a good idea or not</p>



<a name="130235444"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235444" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235444">(Jul 24 2018 at 20:35)</a>:</h4>
<p>but I think it's definitely better than the messages they replace...</p>



<a name="130235593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235593">(Jul 24 2018 at 20:36)</a>:</h4>
<p>ah</p>



<a name="130235710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235710">(Jul 24 2018 at 20:38)</a>:</h4>
<p>Had a question in SO world: Will NLL be enabled by default in Edition 2015 (at some point)? I think yes, other people feel like they've heard no.</p>



<a name="130235887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235887">(Jul 24 2018 at 20:40)</a>:</h4>
<p>I don't think that AST borrowck can be kept around forever</p>



<a name="130235917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130235917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130235917">(Jul 24 2018 at 20:41)</a>:</h4>
<p>That's just tempting fate, to say that ;-)</p>



<a name="130236037"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130236037" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130236037">(Jul 24 2018 at 20:42)</a>:</h4>
<blockquote>
<p>Had a question in SO world: Will NLL be enabled by default in Edition 2015 (at some point)? I think yes, other people feel like they've heard no.</p>
</blockquote>
<p>yes, it will.</p>



<a name="130236139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130236139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130236139">(Jul 24 2018 at 20:44)</a>:</h4>
<p>whew!</p>



<a name="130236157"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130236157" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130236157">(Jul 24 2018 at 20:44)</a>:</h4>
<p>Man, who gets to <code>git rm ast-borrowck</code>...</p>



<a name="130236169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130236169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130236169">(Jul 24 2018 at 20:44)</a>:</h4>
<p>That's my favorite type of code</p>



<a name="130237870"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130237870" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130237870">(Jul 24 2018 at 21:09)</a>:</h4>
<p>re:lifetimes, I usually differentiate lifetimes from scopes, in that only references have lifetimes, and the underlying value lives under a scope</p>



<a name="130237962"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130237962" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130237962">(Jul 24 2018 at 21:11)</a>:</h4>
<p>i don't think it makes a lot of sense to talk about the lifetime of a concrete value (i.e. a non-reference type), since we always know it's valid to be referenced any time, except when it goes out of scope</p>



<a name="130238176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238176">(Jul 24 2018 at 21:14)</a>:</h4>
<blockquote>
<p>except when it goes out of scope</p>
</blockquote>



<a name="130238182"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238182" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238182">(Jul 24 2018 at 21:15)</a>:</h4>
<p>as in, when it is moved? (or also when its lexical scope ends)</p>



<a name="130238255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238255">(Jul 24 2018 at 21:16)</a>:</h4>
<p>sorry I'm being obtuse.  I guess what I mean is: This is not a trivial property. which is exactly why we need to maintain dynamic drop flags</p>



<a name="130238360"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238360" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238360">(Jul 24 2018 at 21:18)</a>:</h4>
<blockquote>
<p>when it is moved?</p>
</blockquote>
<p>yes</p>



<a name="130238382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238382">(Jul 24 2018 at 21:19)</a>:</h4>
<p>i think of lifetimes as basically answering the question, "when/where is this reference safe to be dereferenced?"</p>



<a name="130238439"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238439">(Jul 24 2018 at 21:20)</a>:</h4>
<blockquote>
<p>i don't think it makes a lot of sense to talk about the lifetime of a concrete value</p>
</blockquote>
<p>Except I think that's the intuitive meaning of the word "lifetime", especially for those coming from other languages. It's the time between when the value is "born" and when it "dies". That's why I think that "lifetime" was an unfortunate choice of word.</p>



<a name="130238467"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238467" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238467">(Jul 24 2018 at 21:20)</a>:</h4>
<blockquote>
<p>dynamic drop flags</p>
</blockquote>
<p>remember when these were part of the type, and not on the stack? good times</p>



<a name="130238586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130238586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130238586">(Jul 24 2018 at 21:22)</a>:</h4>
<blockquote>
<p>re:lifetimes, I usually differentiate lifetimes from scopes, in that only references have lifetimes, and the underlying value lives under a scope</p>
</blockquote>
<p>I've tried to push for the terminology of "scopes" being when dtors run etc, but it's hard</p>



<a name="130239050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239050">(Jul 24 2018 at 21:30)</a>:</h4>
<p>English is hard</p>



<a name="130239087"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239087" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239087">(Jul 24 2018 at 21:31)</a>:</h4>
<p>well, wait till you see the chinese translation of "scope"</p>



<a name="130239100"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239100" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239100">(Jul 24 2018 at 21:31)</a>:</h4>
<p>there are two versions of it, one taiwanese and one mainland chinese</p>



<a name="130239171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239171">(Jul 24 2018 at 21:32)</a>:</h4>
<p>the taiwanese version is 生存空间 -- "living space"</p>



<a name="130239177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239177">(Jul 24 2018 at 21:32)</a>:</h4>
<p>the mainland chinese version is 作用域 -- "effective region"</p>



<a name="130239228"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239228" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239228">(Jul 24 2018 at 21:33)</a>:</h4>
<p>i personally think the mainland chinese version captures the essence better</p>



<a name="130239431"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239431" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239431">(Jul 24 2018 at 21:36)</a>:</h4>
<p>Oh, I wasn't meaning that there wasn't <em>harder</em> languages ;-)</p>



<a name="130239457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130239457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130239457">(Jul 24 2018 at 21:37)</a>:</h4>
<p>i think this ties back in to how lifetimes are actually regions in academia</p>



<a name="130271846"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130271846" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130271846">(Jul 25 2018 at 12:21)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> somehow we managed to overlook <a href="https://github.com/rust-lang/rust/issues/45696" target="_blank" title="https://github.com/rust-lang/rust/issues/45696">#45696</a> . <span class="user-mention" data-user-id="116122">@simulacrum</span> caught it but something went wrong it seems</p>



<a name="130271933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130271933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130271933">(Jul 25 2018 at 12:22)</a>:</h4>
<p>hmm.</p>



<a name="130271972"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130271972" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130271972">(Jul 25 2018 at 12:23)</a>:</h4>
<p>(I'm hoping its not an EP2 blocker)</p>



<a name="130271981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130271981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130271981">(Jul 25 2018 at 12:23)</a>:</h4>
<p>but it seems like it should be an RC blocker.</p>



<a name="130281640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281640">(Jul 25 2018 at 15:20)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> so <a href="https://github.com/rust-lang/rust/issues/45696" target="_blank" title="https://github.com/rust-lang/rust/issues/45696">https://github.com/rust-lang/rust/issues/45696</a> .. I had kind of forgotten about dangly paths :)</p>



<a name="130281653"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281653" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281653">(Jul 25 2018 at 15:20)</a>:</h4>
<p>/me tries to bring that back into cache</p>



<a name="130281664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281664">(Jul 25 2018 at 15:21)</a>:</h4>
<p>I could certainly imagine implementing a specialized variant for <code>Box</code> specifically...</p>



<a name="130281780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281780">(Jul 25 2018 at 15:22)</a>:</h4>
<blockquote>
<p>dangly paths</p>
</blockquote>
<p>Please try not to use specialized compiler-writer jargon so the rest of us can follow along <span class="emoji emoji-1f609" title="wink">:wink:</span></p>



<a name="130281815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281815">(Jul 25 2018 at 15:23)</a>:</h4>
<blockquote>
<blockquote>
<p>dangly paths</p>
</blockquote>
<p>Please try not to use specialized compiler-writer jargon so the rest of us can follow along <span class="emoji emoji-1f609" title="wink">:wink:</span></p>
</blockquote>
<p>its sort of hard to avoid in this case</p>



<a name="130281867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281867">(Jul 25 2018 at 15:24)</a>:</h4>
<p>:D</p>



<a name="130281991"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130281991" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130281991">(Jul 25 2018 at 15:26)</a>:</h4>
<p>should branch a thread anyhow</p>



<a name="130288182"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130288182" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130288182">(Jul 25 2018 at 17:01)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> FYI, try builds should be fixed now but we're still in tree closed as macOS builds are not fixed.</p>



<a name="130589417"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130589417" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130589417">(Jul 30 2018 at 16:18)</a>:</h4>
<p>And that was the last we ever saw of <span class="user-mention" data-user-id="116083">@pnkfelix</span> </p>
<p><a href="https://github.com/felix-lang/felix" target="_blank" title="https://github.com/felix-lang/felix">https://github.com/felix-lang/felix</a></p>



<a name="130596497"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130596497" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> DPC <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130596497">(Jul 30 2018 at 18:22)</a>:</h4>
<p>i think if you gather all the people who wrote their own programming language, you will have enough people to host a conference <span class="emoji emoji-1f602" title="joy">:joy:</span></p>



<a name="130597445"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130597445" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130597445">(Jul 30 2018 at 18:38)</a>:</h4>
<blockquote>
<p>And that was the last we ever saw of <span class="user-mention" data-user-id="116083">@pnkfelix</span> </p>
<p><a href="https://github.com/felix-lang/felix" target="_blank" title="https://github.com/felix-lang/felix">https://github.com/felix-lang/felix</a></p>
</blockquote>
<p>Nah, if you ever lose me, it will be to <a href="https://github.com/pnkfelix/larceny" target="_blank" title="https://github.com/pnkfelix/larceny">Scheme</a></p>



<a name="130606596"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130606596" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130606596">(Jul 30 2018 at 21:50)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> are you excited about Dan Friedman and David Christiansen's new book (dependently typed language implementation in Scheme) ? I know I am :) (should be out in a couple weeks)</p>



<a name="130606611"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130606611" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130606611">(Jul 30 2018 at 21:51)</a>:</h4>
<p>Hmm  i actually was not aware of it</p>



<a name="130606617"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130606617" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130606617">(Jul 30 2018 at 21:51)</a>:</h4>
<p>I sort of stopped following Dan Friedman's books at some point</p>



<a name="130606628"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130606628" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130606628">(Jul 30 2018 at 21:51)</a>:</h4>
<p>no real good reason</p>



<a name="130606993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130606993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130606993">(Jul 30 2018 at 21:58)</a>:</h4>
<p><a href="https://github.com/the-little-typer/pie" target="_blank" title="https://github.com/the-little-typer/pie">https://github.com/the-little-typer/pie</a> is the language they'll be making</p>



<a name="130607073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130607073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130607073">(Jul 30 2018 at 22:00)</a>:</h4>
<p>I've heard it's going to be good from people who read it at a previous OPLSS :)</p>



<a name="130609443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609443">(Jul 30 2018 at 22:55)</a>:</h4>
<p>there was a question on IRC and I wasn't sure so I wanted to check here: such cases of "early returns" like <a href="https://play.rust-lang.org/?gist=8f26fab1fcf7438d2739aa5635f443bc&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=8f26fab1fcf7438d2739aa5635f443bc&amp;version=nightly&amp;mode=debug&amp;edition=2015">this</a> are considered out of scope until Polonius ? I <em>feel</em> they are but I also remember some of the conditional control flow examples in the RFC felt somewhat similar.</p>



<a name="130609710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609710">(Jul 30 2018 at 23:03)</a>:</h4>
<p>yes I think that is another example of the kind of control-flow dependent case that we are punting to Polonius</p>



<a name="130609750"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609750" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609750">(Jul 30 2018 at 23:04)</a>:</h4>
<p>It would actually be nice to try to put back the slow code and let us enable it with a debug flag</p>



<a name="130609756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609756">(Jul 30 2018 at 23:04)</a>:</h4>
<p>but then again the slow code did have a maintenance burden</p>



<a name="130609763"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609763" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609763">(Jul 30 2018 at 23:04)</a>:</h4>
<p>yeah it "used to work"</p>



<a name="130609781"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130609781" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130609781">(Jul 30 2018 at 23:05)</a>:</h4>
<p>alright thanks a lot <span class="user-mention" data-user-id="116083">@pnkfelix</span></p>



<a name="130610340"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610340" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610340">(Jul 30 2018 at 23:20)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> any cross-function conditional borrowing, IIRC</p>



<a name="130610349"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610349" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610349">(Jul 30 2018 at 23:20)</a>:</h4>
<p>so you can inline the function and it should work</p>



<a name="130610367"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610367" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610367">(Jul 30 2018 at 23:21)</a>:</h4>
<p>hm interesting</p>



<a name="130610440"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610440" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610440">(Jul 30 2018 at 23:23)</a>:</h4>
<p>I'll try it in their example just in case, thanks Jake</p>



<a name="130610482"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610482" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610482">(Jul 30 2018 at 23:24)</a>:</h4>
<p>but we will make it happen with Polonius!</p>



<a name="130610799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130610799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130610799">(Jul 30 2018 at 23:33)</a>:</h4>
<p>AKA <a href="https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md#problem-case-3-conditional-control-flow-across-functions" target="_blank" title="https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md#problem-case-3-conditional-control-flow-across-functions">NLL case #3</a></p>



<a name="130837904"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130837904" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130837904">(Aug 03 2018 at 13:10)</a>:</h4>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> do you think you'll have time in the near future to address the feedback on PR <a href="https://github.com/rust-lang/rust/issues/52959" target="_blank" title="https://github.com/rust-lang/rust/issues/52959">#52959</a> ?</p>



<a name="130843213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130843213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130843213">(Aug 03 2018 at 14:41)</a>:</h4>
<p>also, by the way... if I <em>don't</em> manage to fix <a href="https://github.com/rust-lang/rust/issues/53026" target="_blank" title="https://github.com/rust-lang/rust/issues/53026">#53026</a>, it is probably the scariest thing that I've seen in a while.</p>



<a name="130843221"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130843221" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130843221">(Aug 03 2018 at 14:41)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ^</p>



<a name="130843233"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130843233" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130843233">(Aug 03 2018 at 14:41)</a>:</h4>
<p>but I'm hoping to identify the root cause.... well, sometime very soon</p>



<a name="130855854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130855854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130855854">(Aug 03 2018 at 18:49)</a>:</h4>
<p>I'll try to have <a href="https://github.com/rust-lang/rust/issues/52959" target="_blank" title="https://github.com/rust-lang/rust/issues/52959">#52959</a> ready for tonight.</p>



<a name="130898509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130898509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Charles Lew <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130898509">(Aug 04 2018 at 17:44)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/49250" target="_blank" title="https://github.com/rust-lang/rust/issues/49250">#49250</a></p>



<a name="130898759"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130898759" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130898759">(Aug 04 2018 at 17:55)</a>:</h4>
<p>at least Matthew's minimized repro doesn't ICE on the playground</p>



<a name="130966673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130966673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130966673">(Aug 06 2018 at 09:09)</a>:</h4>
<p>can i ask what can polonius solve, while MIR borrowck can't?</p>



<a name="130974866"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130974866" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130974866">(Aug 06 2018 at 12:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116108">@Keith Yeung</span> I think the theory is that we’ll be able to implement <em>efficient</em> per-location outlives/subtyping atop Polonius</p>



<a name="130975426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130975426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130975426">(Aug 06 2018 at 12:27)</a>:</h4>
<p>there are also examples that polonius can solve which the older MIR borrowck formulation never code</p>



<a name="130975428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130975428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130975428">(Aug 06 2018 at 12:27)</a>:</h4>
<p>they are linked in the blog post</p>



<a name="130975433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/130975433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#130975433">(Aug 06 2018 at 12:27)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/47680#issuecomment-363131420" target="_blank" title="https://github.com/rust-lang/rust/issues/47680#issuecomment-363131420">here is an example</a></p>



<a name="131000366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131000366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131000366">(Aug 06 2018 at 19:52)</a>:</h4>
<p>i see a lot of issues assigned to <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> on github, are they more of a placeholder or are they actually working on all of the issues assigned to them?</p>



<a name="131001264"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131001264" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131001264">(Aug 06 2018 at 20:09)</a>:</h4>
<p>afaik they are working on them :) but they may be able to say more... :)</p>



<a name="131002234"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131002234" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131002234">(Aug 06 2018 at 20:24)</a>:</h4>
<p>I have <a href="https://github.com/rust-lang/rust/issues/51759" target="_blank" title="https://github.com/rust-lang/rust/issues/51759">#51759</a> as more of a bookmark. I've unassigned myself from <a href="https://github.com/rust-lang/rust/issues/46632" target="_blank" title="https://github.com/rust-lang/rust/issues/46632">#46632</a>. The rest are being worked on and should have PRs soon.</p>



<a name="131003460"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131003460" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131003460">(Aug 06 2018 at 20:49)</a>:</h4>
<p>i've just checked the tests in <a href="https://github.com/rust-lang/rust/issues/46632" target="_blank" title="https://github.com/rust-lang/rust/issues/46632">https://github.com/rust-lang/rust/issues/46632</a>, it looks like all the diagnostics on that one is properly underlining just the head of the closure, instead of the entirety of it</p>



<a name="131005101"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131005101" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131005101">(Aug 06 2018 at 21:25)</a>:</h4>
<p><span class="user-mention" data-user-id="116108">@Keith Yeung</span> if you are looking for a task, maybe <a href="https://github.com/rust-lang/rust/issues/47349" target="_blank" title="https://github.com/rust-lang/rust/issues/47349">https://github.com/rust-lang/rust/issues/47349</a>  might be good?</p>



<a name="131005108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131005108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131005108">(Aug 06 2018 at 21:25)</a>:</h4>
<p>I outlined a strategy for fixing towards the end</p>



<a name="131005113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131005113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131005113">(Aug 06 2018 at 21:25)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/47349#issuecomment-410852205" target="_blank" title="https://github.com/rust-lang/rust/issues/47349#issuecomment-410852205">https://github.com/rust-lang/rust/issues/47349#issuecomment-410852205</a></p>



<a name="131005114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131005114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131005114">(Aug 06 2018 at 21:25)</a>:</h4>
<p>you've read my mind :)</p>



<a name="131009824"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131009824" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131009824">(Aug 06 2018 at 23:30)</a>:</h4>
<p>I'm happy to see all the discussion is nice <code>wg-nll</code>, not in silly old <code>t-compiler</code> today. Boo compiler, yay NLL</p>



<a name="131029943"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131029943" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131029943">(Aug 07 2018 at 08:26)</a>:</h4>
<p>Out of curiosity, how much difference is there between the performance of polonius and non-polonius?</p>



<a name="131030033"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131030033" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131030033">(Aug 07 2018 at 08:28)</a>:</h4>
<p>Also, can someone take a look at why on <a href="https://github.com/rust-lang/rust/issues/53124" target="_blank" title="https://github.com/rust-lang/rust/issues/53124">#53124</a>, <span class="user-mention" data-user-id="116009">@nikomatsakis</span>'s <code>r+</code> comment hasn't done anything?</p>



<a name="131034075"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131034075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131034075">(Aug 07 2018 at 09:57)</a>:</h4>
<blockquote>
<p>Out of curiosity, how much difference is there between the performance of polonius and non-polonius?</p>
</blockquote>
<p>unknown— haven't tried polonius in a while</p>



<a name="131034078"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131034078" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131034078">(Aug 07 2018 at 09:57)</a>:</h4>
<p>a lot of opts we have done apply equally to both</p>



<a name="131034079"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131034079" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131034079">(Aug 07 2018 at 09:57)</a>:</h4>
<p>but not all</p>



<a name="131034277"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131034277" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131034277">(Aug 07 2018 at 10:01)</a>:</h4>
<p>That's why I was wondering.</p>



<a name="131192089"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131192089" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131192089">(Aug 09 2018 at 19:16)</a>:</h4>
<p>i'm having trouble building rustc at home using a windows machine</p>



<a name="131192114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131192114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131192114">(Aug 09 2018 at 19:16)</a>:</h4>
<p>i suspect that they're issues arising from cmake</p>



<a name="131192131"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131192131" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131192131">(Aug 09 2018 at 19:17)</a>:</h4>
<p>does anyone know of such kinds of quirks with rustc?</p>



<a name="131192274"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131192274" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131192274">(Aug 09 2018 at 19:19)</a>:</h4>
<p><span class="user-mention" data-user-id="116108">@Keith Yeung</span> Do you have an error message on hand?</p>



<a name="131194933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131194933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131194933">(Aug 09 2018 at 20:14)</a>:</h4>
<p>unfortunately not, i've since erased my build folder, upgraded my cmake to the latest version and tried to rebuild</p>



<a name="131194942"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/131194942" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#131194942">(Aug 09 2018 at 20:15)</a>:</h4>
<p>now it's complaining about the <code>cmake</code> command not found</p>



<a name="132107138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132107138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132107138">(Aug 14 2018 at 12:18)</a>:</h4>
<p>while adding tests, ran into <a href="https://github.com/rust-lang/rust/issues/21906#issuecomment-389400841" target="_blank" title="https://github.com/rust-lang/rust/issues/21906#issuecomment-389400841">https://github.com/rust-lang/rust/issues/21906#issuecomment-389400841</a></p>



<a name="132107142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132107142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132107142">(Aug 14 2018 at 12:18)</a>:</h4>
<p>is this a regression or deferred for now?</p>



<a name="132108575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108575">(Aug 14 2018 at 12:50)</a>:</h4>
<p>can you say more? what test did you add exactly?</p>



<a name="132108589"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108589" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108589">(Aug 14 2018 at 12:51)</a>:</h4>
<p>in any case, the example from <a href="https://github.com/rust-lang/rust/issues/21906" target="_blank" title="https://github.com/rust-lang/rust/issues/21906">https://github.com/rust-lang/rust/issues/21906</a> is of the kind that polonius aims to fix</p>



<a name="132108590"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108590" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108590">(Aug 14 2018 at 12:51)</a>:</h4>
<p>the tell-tale sign is the conditional return:</p>



<a name="132108597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108597">(Aug 14 2018 at 12:51)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="w">        </span><span class="k">loop</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="kd">let</span><span class="w"> </span><span class="n">k</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">one</span><span class="p">();</span><span class="w"></span>
<span class="w">            </span><span class="k">if</span><span class="w"> </span><span class="o">*</span><span class="n">k</span><span class="w"> </span><span class="o">&gt;</span><span class="w"> </span><span class="mi">10</span><span class="k">i32</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">                </span><span class="k">return</span><span class="w"> </span><span class="n">k</span><span class="p">;</span><span class="w"></span>
<span class="w">            </span><span class="p">}</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
</pre></div>



<a name="132108604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108604">(Aug 14 2018 at 12:51)</a>:</h4>
<p>hmm</p>



<a name="132108608"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108608" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108608">(Aug 14 2018 at 12:51)</a>:</h4>
<p>I wonder if we can target that with an error message</p>



<a name="132108702"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108702" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108702">(Aug 14 2018 at 12:53)</a>:</h4>
<p>Specifically the last two comments, the first one says it built in May, but the second comment said it no longer did. Ah yea, exactly that example!</p>



<a name="132108964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132108964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132108964">(Aug 14 2018 at 12:58)</a>:</h4>
<p>As for the tests, no problems there. I was looking into adding the above example, then read the last two comments. Glad to hear polonius is geared for it ^^. Copying the code samples from <a href="https://github.com/rust-lang/rust/issues/48697" target="_blank" title="https://github.com/rust-lang/rust/issues/48697">https://github.com/rust-lang/rust/issues/48697</a> and <a href="https://github.com/rust-lang/rust/issues/30104" target="_blank" title="https://github.com/rust-lang/rust/issues/30104">https://github.com/rust-lang/rust/issues/30104</a> into a compile-pass ui test</p>



<a name="132113644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132113644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132113644">(Aug 14 2018 at 14:22)</a>:</h4>
<p>meant to add that these tests are originating from issues labeled <code>E-needstest</code></p>



<a name="132286404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132286404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132286404">(Aug 17 2018 at 06:59)</a>:</h4>
<p>nIce! here's what the dashboard would look like when njn's PR lands: <a href="https://perf.rust-lang.org/nll-dashboard.html?commit=496278c16018428a506261e2ed5396168b5c17b9&amp;stat=instructions%3Au" target="_blank" title="https://perf.rust-lang.org/nll-dashboard.html?commit=496278c16018428a506261e2ed5396168b5c17b9&amp;stat=instructions%3Au">dashboard</a></p>



<a name="132288587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132288587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132288587">(Aug 17 2018 at 08:06)</a>:</h4>
<p>wow! <span class="emoji emoji-1f389" title="tada">:tada:</span></p>



<a name="132304146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304146">(Aug 17 2018 at 13:55)</a>:</h4>
<p>What was <span class="user-mention" data-user-id="116009">@nikomatsakis</span>' gut feeling for the cutoff?</p>



<a name="132304149"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304149" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304149">(Aug 17 2018 at 13:55)</a>:</h4>
<p>125% ?</p>



<a name="132304193"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304193" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304193">(Aug 17 2018 at 13:56)</a>:</h4>
<p>20% is what The Research says ... I was shooting for 10% ;)</p>



<a name="132304202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304202">(Aug 17 2018 at 13:56)</a>:</h4>
<p>by The Research I mean what <span class="user-mention" data-user-id="125270">@scottmcm</span> cited from somewhere :)</p>



<a name="132304209"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304209" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304209">(Aug 17 2018 at 13:56)</a>:</h4>
<p>So just a few crates in the benchmark need a boost to hit that</p>



<a name="132304211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304211">(Aug 17 2018 at 13:56)</a>:</h4>
<p>we're getting there</p>



<a name="132304241"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304241" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304241">(Aug 17 2018 at 13:57)</a>:</h4>
<p>probably from <a href="https://www.safaribooksonline.com/library/view/designing-and-engineering/9780321562944/" target="_blank" title="https://www.safaribooksonline.com/library/view/designing-and-engineering/9780321562944/">https://www.safaribooksonline.com/library/view/designing-and-engineering/9780321562944/</a></p>



<a name="132304243"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304243" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304243">(Aug 17 2018 at 13:57)</a>:</h4>
<p>Course, if you factor in the savings of not having to compile a second time just to add some extra <code>{}</code> because AST borrowck...</p>



<a name="132304245"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304245" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304245">(Aug 17 2018 at 13:57)</a>:</h4>
<p>yeah that sounds right</p>



<a name="132304362"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132304362" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132304362">(Aug 17 2018 at 13:59)</a>:</h4>
<p>and there are a couple nice PRs in flight from Wesley and Santiago</p>



<a name="132334301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132334301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132334301">(Aug 18 2018 at 00:04)</a>:</h4>
<p>twist: ends up outperforming current borrowck across the board</p>



<a name="132334304"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132334304" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132334304">(Aug 18 2018 at 00:04)</a>:</h4>
<p>already is with deep-vector :)</p>



<a name="132336149"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132336149" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scottmcm <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132336149">(Aug 18 2018 at 01:04)</a>:</h4>
<p>Yup, that's the one, <span class="user-mention" data-user-id="116113">@lqd</span></p>



<a name="132351276"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132351276" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132351276">(Aug 18 2018 at 08:45)</a>:</h4>
<p>Can someone with bors permissions retry <a href="https://github.com/rust-lang/rust/issues/53175" target="_blank" title="https://github.com/rust-lang/rust/issues/53175">#53175</a>?</p>



<a name="132352197"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132352197" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132352197">(Aug 18 2018 at 09:13)</a>:</h4>
<p><span class="user-mention" data-user-id="125254">@kennytm</span> might be up :) ^</p>



<a name="132354985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132354985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132354985">(Aug 18 2018 at 10:39)</a>:</h4>
<p>Thanks <span class="user-mention" data-user-id="125254">@kennytm</span></p>



<a name="132490612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132490612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132490612">(Aug 21 2018 at 00:50)</a>:</h4>
<p>I just saw this piece of code in a blog post, and I don't understand why it compiles (even with NLL):</p>
<div class="codehilite"><pre><span></span>pub struct Node {
    value: u64,
    next: Option&lt;Box&lt;Node&gt;&gt;,
    prev: Option&lt;Box&lt;Node&gt;&gt;,
}

fn main() {
    // must be mut so we can modify it
    let mut head = Node {
        value: 5,
        next: None,
        prev: None,
    };
    let next = Node {
        value: 6,
        next: None,
                     // next takes ownership of head!!!
        prev: Some(Box::new(head)),
    };
    // I actually don&#39;t understand why the line below compiles.
    // Since `head` was moved into the box, I&#39;m not sure why I can mutate it.
    head.next = Some(Box::new(next));
}
</pre></div>



<a name="132490736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132490736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132490736">(Aug 21 2018 at 00:54)</a>:</h4>
<p>oh wow, and it looks like we have an answer here: <a href="https://github.com/rcoh/rcoh-dot-me-v2/issues/4" target="_blank" title="https://github.com/rcoh/rcoh-dot-me-v2/issues/4">https://github.com/rcoh/rcoh-dot-me-v2/issues/4</a></p>



<a name="132491141"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132491141" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132491141">(Aug 21 2018 at 01:06)</a>:</h4>
<p><span class="user-mention" data-user-id="116108">@Keith Yeung</span> see also <a href="https://github.com/rust-lang/rust/issues/21232" target="_blank" title="https://github.com/rust-lang/rust/issues/21232">https://github.com/rust-lang/rust/issues/21232</a></p>



<a name="132624229"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132624229" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> csmoe <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132624229">(Aug 23 2018 at 08:10)</a>:</h4>
<p>it's an indented behavior in current borrowck, or more specific place check <a href="https://github.com/rust-lang/rust/issues/52669" target="_blank" title="https://github.com/rust-lang/rust/issues/52669">https://github.com/rust-lang/rust/issues/52669</a></p>



<a name="132653463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132653463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132653463">(Aug 23 2018 at 18:26)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/53643" target="_blank" title="https://github.com/rust-lang/rust/issues/53643">#53643</a> is a new contender for huge statics</p>



<a name="132653594"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132653594" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132653594">(Aug 23 2018 at 18:29)</a>:</h4>
<p>I wasn't expecting to see another one of those that soon</p>



<a name="132653614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132653614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132653614">(Aug 23 2018 at 18:29)</a>:</h4>
<p>it would be interesting to try with the SCC + 'static PR</p>



<a name="132653618"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132653618" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132653618">(Aug 23 2018 at 18:30)</a>:</h4>
<p>Are those measurements with the same improvements that helped with the previous huge statics issue?</p>



<a name="132653730"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132653730" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132653730">(Aug 23 2018 at 18:31)</a>:</h4>
<p>at least some of them I think, but not the one which halved html5ever's memory usage, it has yet to land, <a href="https://github.com/rust-lang/rust/issues/53327" target="_blank" title="https://github.com/rust-lang/rust/issues/53327">#53327</a></p>



<a name="132699367"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132699367" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132699367">(Aug 24 2018 at 14:31)</a>:</h4>
<p>oh I was profiling this in the background and didn't notice <span class="user-mention" data-user-id="116009">@nikomatsakis</span> was doing it at the same time; I'll make a PR to add the crate to perf later then</p>



<a name="132699480"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132699480" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132699480">(Aug 24 2018 at 14:33)</a>:</h4>
<p>I have a profile with the SCC+'static PR if that's useful (<a href="https://github.com/rust-lang/rust/issues/53327" target="_blank" title="https://github.com/rust-lang/rust/issues/53327">#53327</a>)</p>



<a name="132699557"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132699557" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132699557">(Aug 24 2018 at 14:35)</a>:</h4>
<p>sounds useful</p>



<a name="132701187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132701187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132701187">(Aug 24 2018 at 15:09)</a>:</h4>
<p>now that my profile on master is done, the two turn out to be so similar to the point of not being useful :3</p>



<a name="132702472"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132702472" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132702472">(Aug 24 2018 at 15:33)</a>:</h4>
<p>but the PR does indeed reduce the memory for this new bench as well: from 2G+ to 1G or so. in any case <a href="https://www.dropbox.com/sh/9wrwrr96prdelot/AADxi83My2YgC3C7dENFET6ha?dl=0" target="_blank" title="https://www.dropbox.com/sh/9wrwrr96prdelot/AADxi83My2YgC3C7dENFET6ha?dl=0">here</a> are the 2 profiles, both in text and native format for qcachegrind.</p>
<div class="message_inline_ref"><a href="https://www.dropbox.com/sh/9wrwrr96prdelot/AADxi83My2YgC3C7dENFET6ha?dl=0" target="_blank" title="ucd"><img src="https://www.dropbox.com/static/images/spectrum-icons/generated/content/content-folder_dropbox-large.png"></a><div><div class="message_inline_image_title">ucd</div><desc class="message_inline_image_desc"></desc></div></div>



<a name="132703895"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132703895" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132703895">(Aug 24 2018 at 16:05)</a>:</h4>
<blockquote>
<p>from 2G+ to 1G </p>
</blockquote>
<p>not shabby 50%</p>



<a name="132791906"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132791906" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132791906">(Aug 26 2018 at 15:21)</a>:</h4>
<p>Is <code>foo.method_takes_mut_self(foo.method_takes_self())</code> handled by "two-phase borrows"? I've never been clear on exactly what that feature means.</p>



<a name="132792044"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792044" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792044">(Aug 26 2018 at 15:26)</a>:</h4>
<p>yes, that example is indeed the whole purpose of that feature</p>



<a name="132792176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792176">(Aug 26 2018 at 15:31)</a>:</h4>
<p>I thought that that much was implemented, was I wrong or was it rolled back?</p>



<a name="132792183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792183">(Aug 26 2018 at 15:32)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="cp">#![feature(nll)]</span><span class="w"></span>
<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="k">mut</span><span class="w"> </span><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">];</span><span class="w"></span>
<span class="w">    </span><span class="n">x</span><span class="p">.</span><span class="n">split_at_mut</span><span class="p">(</span><span class="n">x</span><span class="p">.</span><span class="n">len</span><span class="p">()</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="mi">2</span><span class="p">);</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<div class="codehilite"><pre><span></span>error[E0502]: cannot borrow `*x` as immutable because it is also borrowed as mutable
 --&gt; src/main.rs:4:20
  |
4 |     x.split_at_mut(x.len() / 2);
  |     ---------------^-----------
  |     |              |
  |     |              immutable borrow occurs here
  |     mutable borrow occurs here
  |     borrow later used here
</pre></div>



<a name="132792692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792692">(Aug 26 2018 at 15:50)</a>:</h4>
<p>It is implemented. Not sure why it's not working there. Hmm. Might be worth filing an issue. I would guess it has to do with us inserting more borrows than you might expect.</p>



<a name="132792702"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792702" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792702">(Aug 26 2018 at 15:51)</a>:</h4>
<p>e.g., maybe we desugar that to something like <code>&amp;mut *( &amp;mut *x )</code> or something</p>



<a name="132792706"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792706" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792706">(Aug 26 2018 at 15:51)</a>:</h4>
<p>there are some tricky cases, e.g., if <code>x</code> is a <code>Vec</code>, where the thing we are invoking the method on is actually the result of auto-deref to <code>[]</code></p>



<a name="132792708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792708">(Aug 26 2018 at 15:51)</a>:</h4>
<p>this is (roughly) why things like <code>x[i] += x[j]</code> don't necessarily work</p>



<a name="132792747"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792747" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792747">(Aug 26 2018 at 15:52)</a>:</h4>
<p>or at least one reason</p>



<a name="132792752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792752">(Aug 26 2018 at 15:52)</a>:</h4>
<p>it's annoying that the playground "MIR" option doesn't succeed if there is a borrowck error! :)</p>



<a name="132792798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792798">(Aug 26 2018 at 15:54)</a>:</h4>
<p>in any case, I am slowly becoming convincd that we should consider a more general version -- but I'd prefer to do that in the context of polonius, I <em>think</em> -- or at least to defer thinking about it until we're done with what we've got now. But we might be able to fix this <em>particular</em> example by tweaking how we desugar to try and avoid introducing unnecessary borrows (which would prob just be a general improvement)</p>



<a name="132792972"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792972" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792972">(Aug 26 2018 at 16:01)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ok, clearly I'm missing something - <a href="https://play.rust-lang.org/?gist=ab7e2ad353951d86bc2a17eff93c1049&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=ab7e2ad353951d86bc2a17eff93c1049&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.rust-lang.org/?gist=ab7e2ad353951d86bc2a17eff93c1049&amp;version=nightly&amp;mode=debug&amp;edition=2015</a></p>



<a name="132792978"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792978" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792978">(Aug 26 2018 at 16:01)</a>:</h4>
<p>there's no possibility for desugaring here, right?</p>



<a name="132792979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792979">(Aug 26 2018 at 16:01)</a>:</h4>
<p>you had <code>#[feature(nll)]</code></p>



<a name="132792980"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792980" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792980">(Aug 26 2018 at 16:01)</a>:</h4>
<p>try <code>#![feature(nll)]</code></p>



<a name="132792981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792981">(Aug 26 2018 at 16:02)</a>:</h4>
<p>feh</p>



<a name="132792982"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132792982" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132792982">(Aug 26 2018 at 16:02)</a>:</h4>
<p>that <a href="https://play.rust-lang.org/?gist=dad0a7efd3f68b5239985badc86e1f49&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=dad0a7efd3f68b5239985badc86e1f49&amp;version=nightly&amp;mode=debug&amp;edition=2015">works for me</a></p>



<a name="132793022"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793022" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793022">(Aug 26 2018 at 16:02)</a>:</h4>
<p>whew</p>



<a name="132793024"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793024" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793024">(Aug 26 2018 at 16:02)</a>:</h4>
<p>and I didn't make the same mistake for <code>split_at_mut</code>, good</p>



<a name="132793030"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793030" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793030">(Aug 26 2018 at 16:03)</a>:</h4>
<p>well, sort of good :P</p>



<a name="132793031"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793031" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793031">(Aug 26 2018 at 16:03)</a>:</h4>
<p>/me would rather you had</p>



<a name="132793032"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793032" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793032">(Aug 26 2018 at 16:03)</a>:</h4>
<p>good for <em>me</em>, not for <em>Rust</em></p>



<a name="132793075"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793075">(Aug 26 2018 at 16:04)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/53723" target="_blank" title="https://github.com/rust-lang/rust/issues/53723">https://github.com/rust-lang/rust/issues/53723</a>. I tagged as NLL but didn't go deeper. Not sure how y'all are playing your tags these days</p>



<a name="132793602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793602">(Aug 26 2018 at 16:24)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> as I'm idling in #rust, I realize I really appreciate that you put forth effort to consistently use "they" / "them" on the Internet. Thanks for that <span class="emoji emoji-2764" title="heart">:heart:</span>️</p>



<a name="132793658"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793658" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793658">(Aug 26 2018 at 16:26)</a>:</h4>
<blockquote>
<p>it's annoying that the playground "MIR" option doesn't succeed if there is a borrowck error! :)</p>
</blockquote>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> I just do <code>--emit=mir</code> — is there a file output even when the compiler returns non-zero?</p>



<a name="132793662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793662">(Aug 26 2018 at 16:27)</a>:</h4>
<p>well, you'd have to use <code>-Zdump-mir</code></p>



<a name="132793665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793665">(Aug 26 2018 at 16:27)</a>:</h4>
<p>which dumps the MIR at each stage</p>



<a name="132793669"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793669" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793669">(Aug 26 2018 at 16:27)</a>:</h4>
<p>you could imagine having multiple MIR options, e.g. pre-opt and post-opt</p>



<a name="132793670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793670">(Aug 26 2018 at 16:27)</a>:</h4>
<p>not that there is much difference now</p>



<a name="132793671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793671">(Aug 26 2018 at 16:27)</a>:</h4>
<p>but there is some</p>



<a name="132793769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132793769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132793769">(Aug 26 2018 at 16:30)</a>:</h4>
<p><code>-Z</code> so it's nightly only, yeah? And this produces an undefined number of MIR files?</p>



<a name="132794472"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132794472" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132794472">(Aug 26 2018 at 16:56)</a>:</h4>
<p>yes to both</p>



<a name="132867237"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132867237" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132867237">(Aug 27 2018 at 16:32)</a>:</h4>
<blockquote>
<p>&lt;Dodo&gt; <a href="https://play.rust-lang.org/?gist=a2cddd874bbe8af95ce9d35f98a16aa2&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=a2cddd874bbe8af95ce9d35f98a16aa2&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.rust-lang.org/?gist=a2cddd874bbe8af95ce9d35f98a16aa2&amp;version=nightly&amp;mode=debug&amp;edition=2015</a><br>
12:17 PM such a nice message :)<br>
12:27 PM &lt;andytoshi&gt; wow, that is a really cool message<br>
12:28 PM very close to my IRC explanation</p>
</blockquote>



<a name="132867243"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132867243" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132867243">(Aug 27 2018 at 16:32)</a>:</h4>
<p>Yay for NLL error messages!</p>



<a name="132886067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132886067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132886067">(Aug 27 2018 at 23:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <a href="https://github.com/rust-lang/rust/issues/47184#issuecomment-416396531" target="_blank" title="https://github.com/rust-lang/rust/issues/47184#issuecomment-416396531">your comment</a> got cut off "(Then we could fix"</p>



<a name="132886431"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132886431" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132886431">(Aug 27 2018 at 23:28)</a>:</h4>
<p>no idea what I wanted there...</p>



<a name="132933566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933566">(Aug 28 2018 at 18:21)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> <a href="https://github.com/rust-lang/rust/issues/47184#issuecomment-416669986" target="_blank" title="https://github.com/rust-lang/rust/issues/47184#issuecomment-416669986">your keyboard slipped away again</a> "In particular, when we lower"</p>



<a name="132933590"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933590" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933590">(Aug 28 2018 at 18:21)</a>:</h4>
<p>test test</p>



<a name="132933649"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933649" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933649">(Aug 28 2018 at 18:22)</a>:</h4>
<p>I think I just meant to kill those last two paragraphs</p>



<a name="132933652"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933652" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933652">(Aug 28 2018 at 18:22)</a>:</h4>
<p>thanks for being my copy editor :P</p>



<a name="132933679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933679">(Aug 28 2018 at 18:23)</a>:</h4>
<p>Nah, if I were doing that, I'd just edit it. It's more that I'm hanging on every word!</p>



<a name="132933787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933787">(Aug 28 2018 at 18:25)</a>:</h4>
<p>lol</p>



<a name="132933854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933854">(Aug 28 2018 at 18:26)</a>:</h4>
<p>I'm sure I've used some horrible grammatical monstrosities as well</p>



<a name="132933862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933862">(Aug 28 2018 at 18:26)</a>:</h4>
<p>that you have graciously resisted pointing out</p>



<a name="132933990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132933990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132933990">(Aug 28 2018 at 18:29)</a>:</h4>
<p>Eh. Different forums have different needs. SO is meant to be a "forever repository" so I care more about that. Ditto RFCs. GitHub, URLO/IRLO are more fluid, Zulip/IRC/Discord/Gitter even more so.</p>



<a name="132934067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934067">(Aug 28 2018 at 18:30)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> regarding your chaining iterator, I'd say that <code>Either</code> is far more common, but your point about efficiency is interesting. Would be  neat to see how they compare</p>



<a name="132934124"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934124" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934124">(Aug 28 2018 at 18:31)</a>:</h4>
<p>Either is a more mechanical transformation, to be sure</p>



<a name="132934163"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934163" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934163">(Aug 28 2018 at 18:32)</a>:</h4>
<p>I guess it will depend on how many items you are iterating over</p>



<a name="132934170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934170">(Aug 28 2018 at 18:32)</a>:</h4>
<p>since it is sort of a "proportional" price</p>



<a name="132934181"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934181" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934181">(Aug 28 2018 at 18:32)</a>:</h4>
<p>and of course how much work you're doing</p>



<a name="132934185"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934185" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934185">(Aug 28 2018 at 18:32)</a>:</h4>
<p>it seems..unlikely to really matter</p>



<a name="132934224"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934224" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934224">(Aug 28 2018 at 18:33)</a>:</h4>
<p>I don't know why the "option variant" appeals to me so</p>



<a name="132934227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934227">(Aug 28 2018 at 18:33)</a>:</h4>
<p>I guess it's the "flatenning" aspect</p>



<a name="132934229"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934229" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934229">(Aug 28 2018 at 18:33)</a>:</h4>
<p>I dislike ifs :P</p>



<a name="132934235"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934235" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934235">(Aug 28 2018 at 18:33)</a>:</h4>
<p>/me is aware that there are actually ifs either way</p>



<a name="132934247"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934247" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934247">(Aug 28 2018 at 18:33)</a>:</h4>
<p>I also haven't looked closely at thow the "exact len iterator" and other such traits business propagates</p>



<a name="132934251"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934251" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934251">(Aug 28 2018 at 18:33)</a>:</h4>
<p>I think that is perhaps more important</p>



<a name="132934298"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934298" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934298">(Aug 28 2018 at 18:34)</a>:</h4>
<p>but in principle it could be propagated either way</p>



<a name="132934311"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934311" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934311">(Aug 28 2018 at 18:34)</a>:</h4>
<p>Would you care to add this variant to <a href="https://stackoverflow.com/questions/29760668/conditionally-iterate-over-one-of-several-possible-iterators" target="_blank" title="https://stackoverflow.com/questions/29760668/conditionally-iterate-over-one-of-several-possible-iterators">https://stackoverflow.com/questions/29760668/conditionally-iterate-over-one-of-several-possible-iterators</a> ?</p>



<a name="132934484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934484">(Aug 28 2018 at 18:37)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="k">use</span><span class="w"> </span><span class="n">std</span>::<span class="n">iter</span><span class="p">;</span><span class="w"></span>

<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">x</span>: <span class="nb">Option</span><span class="o">&lt;</span><span class="kt">i64</span><span class="o">&gt;</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">None</span><span class="p">;</span><span class="w"></span>

<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">a</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">b</span><span class="p">;</span><span class="w"></span>

<span class="w">    </span><span class="k">match</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="nb">None</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="n">a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="mi">1</span><span class="p">..</span><span class="mi">5</span><span class="p">);</span><span class="w"></span>
<span class="w">            </span><span class="n">b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">None</span><span class="p">;</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">        </span><span class="nb">Some</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="o">=&gt;</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">            </span><span class="n">a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">None</span><span class="p">;</span><span class="w"></span>
<span class="w">            </span><span class="n">b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">Some</span><span class="p">(</span><span class="n">iter</span>::<span class="n">repeat</span><span class="p">(</span><span class="n">x</span><span class="p">).</span><span class="n">take</span><span class="p">(</span><span class="mi">5</span><span class="p">));</span><span class="w"></span>
<span class="w">        </span><span class="p">}</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>

<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">c</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">a</span><span class="w"></span>
<span class="w">        </span><span class="p">.</span><span class="n">into_iter</span><span class="p">()</span><span class="w"></span>
<span class="w">        </span><span class="p">.</span><span class="n">flat_map</span><span class="p">(</span><span class="o">|</span><span class="n">x</span><span class="o">|</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"></span>
<span class="w">        </span><span class="p">.</span><span class="n">chain</span><span class="p">(</span><span class="n">b</span><span class="p">.</span><span class="n">into_iter</span><span class="p">().</span><span class="n">flat_map</span><span class="p">(</span><span class="o">|</span><span class="n">x</span><span class="o">|</span><span class="w"> </span><span class="n">x</span><span class="p">));</span><span class="w"></span>

<span class="w">    </span><span class="c1">// Repeat x 5 times if present, otherwise count from 1 to 5</span>
<span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">c</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">        </span><span class="n">println</span><span class="o">!</span><span class="p">(</span><span class="s">&quot;{}&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">i</span><span class="p">);</span><span class="w"></span>
<span class="w">    </span><span class="p">}</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>


<p>Not quite as pretty, if I did it right.</p>



<a name="132934663"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934663" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934663">(Aug 28 2018 at 18:40)</a>:</h4>
<p>I'm debating if what I said about perf is really true</p>



<a name="132934764"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934764" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934764">(Aug 28 2018 at 18:42)</a>:</h4>
<p>chain would need to check every <code>next</code> call for <code>None</code>, either would check the enum for every next call</p>



<a name="132934861"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934861" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934861">(Aug 28 2018 at 18:44)</a>:</h4>
<p>(posted)</p>



<a name="132934865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934865">(Aug 28 2018 at 18:44)</a>:</h4>
<p>I left out commentary about perf</p>



<a name="132934867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934867">(Aug 28 2018 at 18:44)</a>:</h4>
<p>since it's...complex</p>



<a name="132934872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132934872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132934872">(Aug 28 2018 at 18:44)</a>:</h4>
<p>might be a win, might not</p>



<a name="132935003"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132935003" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132935003">(Aug 28 2018 at 18:47)</a>:</h4>
<p>thanks!</p>



<a name="132991308"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991308" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991308">(Aug 29 2018 at 11:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> RE: <a href="https://github.com/rust-lang/rust/issues/53643#issuecomment-416923045" target="_blank" title="https://github.com/rust-lang/rust/issues/53643#issuecomment-416923045">https://github.com/rust-lang/rust/issues/53643#issuecomment-416923045</a> the memory issue is greatly reduced by <a href="https://github.com/rust-lang/rust/issues/53327" target="_blank" title="https://github.com/rust-lang/rust/issues/53327">#53327</a> <a href="https://github.com/rust-lang/rust/pull/53327#issuecomment-416623319" target="_blank" title="https://github.com/rust-lang/rust/pull/53327#issuecomment-416623319">https://github.com/rust-lang/rust/pull/53327#issuecomment-416623319</a></p>



<a name="132991467"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991467" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991467">(Aug 29 2018 at 11:59)</a>:</h4>
<p>But by “only” 50%, right?</p>



<a name="132991524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991524">(Aug 29 2018 at 12:00)</a>:</h4>
<p>I thought Simon reported a much more grave regression</p>



<a name="132991525"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991525" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991525">(Aug 29 2018 at 12:00)</a>:</h4>
<p>67%</p>



<a name="132991529"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991529" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991529">(Aug 29 2018 at 12:00)</a>:</h4>
<p>Hmm ok</p>



<a name="132991539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991539">(Aug 29 2018 at 12:00)</a>:</h4>
<p>it is "reduced" but I wouldn't say "fixed" or inexistant for sure</p>



<a name="132991556"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991556" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991556">(Aug 29 2018 at 12:01)</a>:</h4>
<p>Oh oh I now see</p>



<a name="132991559"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991559" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991559">(Aug 29 2018 at 12:01)</a>:</h4>
<p>I misread Simon’s comment</p>



<a name="132991564"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991564" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991564">(Aug 29 2018 at 12:01)</a>:</h4>
<p>ie it will go from 542,664K to 772,052K once the PR lands</p>



<a name="132991604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991604">(Aug 29 2018 at 12:02)</a>:</h4>
<p>He mentioned a second worse regesssion, but that was <em>before</em> the current nightly</p>



<a name="132991616"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991616" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991616">(Aug 29 2018 at 12:02)</a>:</h4>
<p>yeah exactly</p>



<a name="132991727"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132991727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132991727">(Aug 29 2018 at 12:05)</a>:</h4>
<p>(it was a nightly from mid july causing problems; which was before the other memory work for html5ever IIRC)</p>



<a name="132995233"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132995233" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132995233">(Aug 29 2018 at 13:11)</a>:</h4>
<p>oh the "new" try blocks require edition 2018</p>



<a name="132995285"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132995285" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132995285">(Aug 29 2018 at 13:12)</a>:</h4>
<p>I was confused by these errors in Polonius on edition 2015 <a href="https://play.rust-lang.org/?gist=77369449a113b0c04383f0365d8bf28e&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=77369449a113b0c04383f0365d8bf28e&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.rust-lang.org/?gist=77369449a113b0c04383f0365d8bf28e&amp;version=nightly&amp;mode=debug&amp;edition=2015</a></p>



<a name="132995694"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132995694" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132995694">(Aug 29 2018 at 13:19)</a>:</h4>
<p>#![feature(rust_2018_preview)] is not enough ?! wat</p>



<a name="132998042"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132998042" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132998042">(Aug 29 2018 at 14:01)</a>:</h4>
<p>polonius is just broken I think?</p>



<a name="132998161"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132998161" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132998161">(Aug 29 2018 at 14:03)</a>:</h4>
<p>opting into the edition from Cargo.toml is the only way I managed to make it work</p>



<a name="132998184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132998184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132998184">(Aug 29 2018 at 14:03)</a>:</h4>
<p>it might also be the correct way to make it work :)</p>



<a name="132999174"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/132999174" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Basile Desloges <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#132999174">(Aug 29 2018 at 14:20)</a>:</h4>
<p>Hey everyone!</p>
<p>I'd like to work on NLL, is there a list of starter issues where I should pick one or should I just pick an issue in <a href="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-NLL" target="_blank" title="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-NLL">https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-NLL</a> ? (if that's the second case, any recommendation?)</p>



<a name="133003863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133003863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133003863">(Aug 29 2018 at 15:32)</a>:</h4>
<p>Hi <span class="user-mention" data-user-id="127686">@Basile Desloges</span> ; you may want to look over the list of issues that were discussed at the meeting last night, as documented in the <a href="https://paper.dropbox.com/doc/Non-lexical-lifetimes-NLL-Triage-Em2cJrvxQMMFWLE7lE5Be" target="_blank" title="https://paper.dropbox.com/doc/Non-lexical-lifetimes-NLL-Triage-Em2cJrvxQMMFWLE7lE5Be">triage Paper</a></p>



<a name="133003938"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133003938" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Basile Desloges <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133003938">(Aug 29 2018 at 15:33)</a>:</h4>
<p>Thanks! I'll take a look :)</p>



<a name="133010135"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133010135" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133010135">(Aug 29 2018 at 17:26)</a>:</h4>
<p>(teasing yet again, -13% in leapfrog)</p>



<a name="133013701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013701">(Aug 29 2018 at 18:35)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> are things in any kind of state to compare datafrog perf vs mainline compiler?</p>



<a name="133013791"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013791" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013791">(Aug 29 2018 at 18:37)</a>:</h4>
<p>interesting question, I don't <em>think</em> so</p>



<a name="133013808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013808">(Aug 29 2018 at 18:37)</a>:</h4>
<p>absolutely not</p>



<a name="133013818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013818">(Aug 29 2018 at 18:37)</a>:</h4>
<p>e.g. the subtyping code is not creating facts</p>



<a name="133013863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013863">(Aug 29 2018 at 18:38)</a>:</h4>
<p>we have to go back and try to fix up polonius support at some point...</p>



<a name="133013899"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133013899" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133013899">(Aug 29 2018 at 18:39)</a>:</h4>
<p>(and our best strategy in polonius itself isn't fully baked / available / 100% correct yet)</p>



<a name="133014022"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014022" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014022">(Aug 29 2018 at 18:41)</a>:</h4>
<p>also: it doesn't build :p</p>



<a name="133014104"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014104" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014104">(Aug 29 2018 at 18:43)</a>:</h4>
<p>if would be cool to know what needs to be done fo fix up polonius support, maybe it can be done in the background of the current work, or by new contributors etc</p>



<a name="133014110"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014110" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014110">(Aug 29 2018 at 18:43)</a>:</h4>
<p>or by <span class="user-mention" data-user-id="116155">@Jake Goulding</span></p>



<a name="133014172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014172">(Aug 29 2018 at 18:44)</a>:</h4>
<p>Man... there's so much lacking knowledge in this brain between here and there</p>



<a name="133014177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014177">(Aug 29 2018 at 18:44)</a>:</h4>
<p>I could make it build again, maybe. And last I heard, it should be easy to get all the tests passing again ;-).</p>



<a name="133014297"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133014297" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133014297">(Aug 29 2018 at 18:46)</a>:</h4>
<p>(I got it to build earlier, which is where that tiny bench came from, just needs to opt in the 2018 edition, switch the catch_exprs fleature flag to try_blocks, and s/do catch/ try/g)</p>



<a name="133147454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133147454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133147454">(Aug 31 2018 at 20:43)</a>:</h4>
<p>ran across two untagged nll/borrowcheck related issues<br>
<a href="https://github.com/rust-lang/rust/issues/53528" target="_blank" title="https://github.com/rust-lang/rust/issues/53528">https://github.com/rust-lang/rust/issues/53528</a><br>
<a href="https://github.com/rust-lang/rust/issues/52706" target="_blank" title="https://github.com/rust-lang/rust/issues/52706">https://github.com/rust-lang/rust/issues/52706</a></p>



<a name="133192030"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133192030" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133192030">(Sep 01 2018 at 21:49)</a>:</h4>
<p>Is everyone happy with removing the "not reporting region error due to nll" warning? (cf. <a href="https://github.com/rust-lang/rust/issues/53865" target="_blank" title="https://github.com/rust-lang/rust/issues/53865">#53865</a>)</p>



<a name="133306618"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133306618" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133306618">(Sep 04 2018 at 11:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> is there anything I can help you with <a href="https://github.com/rust-lang/rust/issues/52934" target="_blank" title="https://github.com/rust-lang/rust/issues/52934">#52934</a> ?</p>



<a name="133306631"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133306631" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133306631">(Sep 04 2018 at 11:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span> nope, I'm about done writing a test I think</p>



<a name="133306649"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133306649" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133306649">(Sep 04 2018 at 11:58)</a>:</h4>
<p>It just took me a little while because I wanted to try to enumerate various cases in the design space</p>



<a name="133306671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133306671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133306671">(Sep 04 2018 at 11:59)</a>:</h4>
<p>sorry I wasn't able to look at it earlier, you had done a ton of work already when I was able to look at the issue</p>



<a name="133323619"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133323619" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133323619">(Sep 04 2018 at 17:18)</a>:</h4>
<p>I've now had two instances where a PR (different PRs) will build locally but on Travis fails with a lifetime error - anyone know what might be causing tha?</p>



<a name="133323872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133323872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133323872">(Sep 04 2018 at 17:23)</a>:</h4>
<p><span class="user-mention" data-user-id="116107">@davidtwco</span> usually this indicates that you need to rebase, as travis tests post-merge</p>



<a name="133323877"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133323877" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133323877">(Sep 04 2018 at 17:23)</a>:</h4>
<p>could it be that?</p>



<a name="133323958"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133323958" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133323958">(Sep 04 2018 at 17:24)</a>:</h4>
<p>It doesn't feel like it is. I've seen it <a href="https://github.com/rust-lang/rust/pull/53900#issuecomment-418447270" target="_blank" title="https://github.com/rust-lang/rust/pull/53900#issuecomment-418447270">here</a> and <a href="https://github.com/rust-lang/rust/pull/53830#issuecomment-417418159" target="_blank" title="https://github.com/rust-lang/rust/pull/53830#issuecomment-417418159">here (I think this was it)</a>.</p>



<a name="133324007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133324007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133324007">(Sep 04 2018 at 17:25)</a>:</h4>
<p>From what I can remember, in the latter PR there, I rebased locally and still couldn't reproduce, I just best-guess moved a function call and that satisfied it.</p>



<a name="133324077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133324077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133324077">(Sep 04 2018 at 17:26)</a>:</h4>
<p>They seem like the type of errors that I wouldn't expect a rebase to cause.</p>



<a name="133324518"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133324518" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133324518">(Sep 04 2018 at 17:34)</a>:</h4>
<p>In this case it might have been a rebase issue, ignore me. <span class="emoji emoji-1f926" title="face palm">:face_palm:</span></p>



<a name="133435514"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435514" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435514">(Sep 06 2018 at 11:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I think <a href="https://github.com/rust-lang/rust/issues/43234#issuecomment-419030308" target="_blank" title="https://github.com/rust-lang/rust/issues/43234#issuecomment-419030308">https://github.com/rust-lang/rust/issues/43234#issuecomment-419030308</a> should be sent to rfcbot instead of bors</p>



<a name="133435523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435523">(Sep 06 2018 at 11:14)</a>:</h4>
<p>oh of course</p>



<a name="133435551"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435551" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435551">(Sep 06 2018 at 11:15)</a>:</h4>
<p>we should have numbers comparing to incremental this afternoon</p>



<a name="133435703"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435703" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435703">(Sep 06 2018 at 11:19)</a>:</h4>
<p>hmm is rfcbot notified when messages are edited ? looks like they didn't go through to <a href="https://github.com/rust-lang/rust/issues/43234#issuecomment-410263039" target="_blank" title="https://github.com/rust-lang/rust/issues/43234#issuecomment-410263039">https://github.com/rust-lang/rust/issues/43234#issuecomment-410263039</a></p>



<a name="133435709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435709">(Sep 06 2018 at 11:19)</a>:</h4>
<p>yeah I think I'll just delete and repost</p>



<a name="133435771"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435771" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435771">(Sep 06 2018 at 11:20)</a>:</h4>
<p>although even <em>that</em> doesn't seem to have worked?</p>



<a name="133435774"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435774" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435774">(Sep 06 2018 at 11:21)</a>:</h4>
<p>I think it did</p>



<a name="133435786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435786">(Sep 06 2018 at 11:21)</a>:</h4>
<p>all concerns look resolved now</p>



<a name="133435788"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133435788" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133435788">(Sep 06 2018 at 11:21)</a>:</h4>
<p>oh okay, something was not handled right in my page load</p>



<a name="133438777"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133438777" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133438777">(Sep 06 2018 at 12:30)</a>:</h4>
<p>and <a href="https://perf.rust-lang.org/compare.html?start=b0297f3043e4ed592c63c0bcc11df3655ec8cf46&amp;end=3a8b7311d49570250afdeba6b45e5e7de7bca050" target="_blank" title="https://perf.rust-lang.org/compare.html?start=b0297f3043e4ed592c63c0bcc11df3655ec8cf46&amp;end=3a8b7311d49570250afdeba6b45e5e7de7bca050">here are the numbers</a> for the migrate mode</p>



<a name="133440891"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133440891" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133440891">(Sep 06 2018 at 13:11)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span> anyone want to review <a href="https://github.com/rust-lang/rust/issues/53948" target="_blank" title="https://github.com/rust-lang/rust/issues/53948">#53948</a> ? I think its "trivial" enough that anyone in the WG is qualified to look it over. (Mostly a sanity check)</p>



<a name="133441080"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133441080" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133441080">(Sep 06 2018 at 13:14)</a>:</h4>
<p>(i'm going to assign it to niko in the meantime, but my intention is that anyone can review it.)</p>



<a name="133441737"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133441737" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133441737">(Sep 06 2018 at 13:27)</a>:</h4>
<p>I got it. Thanks for the assist <span class="user-mention" data-user-id="116083">@pnkfelix</span>!</p>



<a name="133441752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133441752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133441752">(Sep 06 2018 at 13:27)</a>:</h4>
<p>thanks to <em>you</em> Wesley. :)</p>



<a name="133449947"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133449947" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133449947">(Sep 06 2018 at 15:28)</a>:</h4>
<p>Just looking through the <a href="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-NLL+milestone%3A%22Rust+2018+RC%22+no%3Aassignee" target="_blank" title="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AA-NLL+milestone%3A%22Rust+2018+RC%22+no%3Aassignee">RC milestone issues</a> - the following issues read to me as if there are unresolved discussions or something that makes it a tad unclear what needs done:</p>
<p><a href="https://github.com/rust-lang/rust/issues/53114" target="_blank" title="https://github.com/rust-lang/rust/issues/53114">#53114</a>, <a href="https://github.com/rust-lang/rust/issues/53040" target="_blank" title="https://github.com/rust-lang/rust/issues/53040">#53040</a>, <a href="https://github.com/rust-lang/rust/issues/51269" target="_blank" title="https://github.com/rust-lang/rust/issues/51269">#51269</a></p>
<p>I've got an issue to work on at the moment, but of the seven unassigned milestone issues, four aren't tracking/list issues of some kind and three of those read as unclear. IMO might be worth looking over those to clarify what is needing done since we normally point people looking for a issue at that list.</p>



<a name="133461184"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133461184" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133461184">(Sep 06 2018 at 18:42)</a>:</h4>
<p>maybe/esp the ICE <span class="emoji emoji-1f44d" title="thumbs up">:thumbs_up:</span></p>



<a name="133498547"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133498547" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133498547">(Sep 07 2018 at 09:00)</a>:</h4>
<p>(btw the last 2 of these 3 issues are now no longer on the RC milestone)</p>



<a name="133521035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521035">(Sep 07 2018 at 16:10)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> is it <code>x.py test src/tools/tidy</code> to run tidy locally that you find inconvenient ? we'd maybe want a <code>x.py tidy</code> ?</p>



<a name="133521356"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521356" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521356">(Sep 07 2018 at 16:15)</a>:</h4>
<p>actually ignore me</p>



<a name="133521358"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521358" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521358">(Sep 07 2018 at 16:15)</a>:</h4>
<p>Which complaint of mine are you referring to?</p>



<a name="133521365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521365">(Sep 07 2018 at 16:15)</a>:</h4>
<p>On the rustc-guide?</p>



<a name="133521368"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521368" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521368">(Sep 07 2018 at 16:15)</a>:</h4>
<p>As it happens, I do find that annoying :)</p>



<a name="133521369"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521369" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521369">(Sep 07 2018 at 16:15)</a>:</h4>
<p><a href="https://github.com/rust-lang-nursery/rustc-guide/pull/190#issuecomment-419475202" target="_blank" title="https://github.com/rust-lang-nursery/rustc-guide/pull/190#issuecomment-419475202">https://github.com/rust-lang-nursery/rustc-guide/pull/190#issuecomment-419475202</a></p>



<a name="133521373"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521373" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521373">(Sep 07 2018 at 16:15)</a>:</h4>
<p>right :(</p>



<a name="133521378"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521378" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521378">(Sep 07 2018 at 16:15)</a>:</h4>
<p>yeah, however, the rustc-guide one is even more annoying</p>



<a name="133521380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521380">(Sep 07 2018 at 16:15)</a>:</h4>
<p>I misread it as regular rust repo sorry :((((((</p>



<a name="133521392"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521392" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521392">(Sep 07 2018 at 16:15)</a>:</h4>
<p>:)</p>



<a name="133521394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521394">(Sep 07 2018 at 16:15)</a>:</h4>
<p>afaict <code>MAX_LINE_LENGTH=80 ci/check_line_lengths.sh src/**/*.md</code> is what you have to do there...</p>



<a name="133521395"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521395" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521395">(Sep 07 2018 at 16:15)</a>:</h4>
<p>i should just make a bash script</p>



<a name="133521396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521396">(Sep 07 2018 at 16:15)</a>:</h4>
<p>something needs to be done about this lint to make it more ergonomic</p>



<a name="133521447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521447">(Sep 07 2018 at 16:16)</a>:</h4>
<p>or a makefile or something</p>



<a name="133521457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521457">(Sep 07 2018 at 16:16)</a>:</h4>
<p>alias lint_of_doom=</p>



<a name="133521889"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133521889" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133521889">(Sep 07 2018 at 16:25)</a>:</h4>
<p>part of it is that I'm just grumpy today :) I have to go to the dentist, that never helps! <span class="emoji emoji-1f628" title="scared">:scared:</span></p>



<a name="133522153"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133522153" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133522153">(Sep 07 2018 at 16:30)</a>:</h4>
<p>:/</p>



<a name="133522156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133522156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133522156">(Sep 07 2018 at 16:30)</a>:</h4>
<p>hang in there :D</p>



<a name="133526146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133526146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133526146">(Sep 07 2018 at 17:44)</a>:</h4>
<p>w/r/t being able to spot a long line:</p>
<p>In Vim, I have the following set which adds a vertical bar at a certain column, might be useful to some:</p>
<div class="codehilite"><pre><span></span><span class="c">&quot; Colour 40 columns after column 80.</span>
<span class="k">let</span> &amp;<span class="nb">colorcolumn</span><span class="p">=</span><span class="s2">&quot;100,&quot;</span>.<span class="k">join</span><span class="p">(</span>range<span class="p">(</span><span class="m">140</span><span class="p">,</span> <span class="m">1000</span><span class="p">,</span> <span class="m">40</span><span class="p">),</span> <span class="s2">&quot;,&quot;</span><span class="p">)</span>
</pre></div>



<a name="133526445"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133526445" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133526445">(Sep 07 2018 at 17:50)</a>:</h4>
<p>inb4 #wg-nll splits into #wg-nll-vim and #wg-nll-emacs</p>



<a name="133529168"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133529168" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133529168">(Sep 07 2018 at 18:40)</a>:</h4>
<p>it has already split between #wg-nll-mir and #wg-nll-frog</p>



<a name="133815350"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815350" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815350">(Sep 12 2018 at 17:55)</a>:</h4>
<p>Does anyone remember the magic keywords I can search for for "llvm deduplicates identical function bodies"</p>



<a name="133815361"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815361" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815361">(Sep 12 2018 at 17:55)</a>:</h4>
<p>I know that it was turned off for a while, then turned back on "recently", but I cant figure out when and what that feature was called to search for it</p>



<a name="133815704"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815704" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815704">(Sep 12 2018 at 18:01)</a>:</h4>
<p>yeah just a sec</p>



<a name="133815830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815830">(Sep 12 2018 at 18:03)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> the magic keyword is <code>mergefunc</code>, and the recent PR is <a href="https://github.com/rust-lang/rust/pull/49479" target="_blank" title="https://github.com/rust-lang/rust/pull/49479">https://github.com/rust-lang/rust/pull/49479</a></p>



<a name="133815890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815890">(Sep 12 2018 at 18:04)</a>:</h4>
<p>Thank you!</p>



<a name="133815904"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133815904" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133815904">(Sep 12 2018 at 18:04)</a>:</h4>
<p>np</p>



<a name="133875939"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133875939" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133875939">(Sep 13 2018 at 10:53)</a>:</h4>
<p>hey does anyone remember if there was a github issue discussing attempting to encode things like "<code>Option&lt;S&lt;'a&gt;&gt;</code> cannot possibly keep the lifetime alive across a None branch of a <code>match</code>"?</p>



<a name="133875942"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133875942" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133875942">(Sep 13 2018 at 10:54)</a>:</h4>
<p>I've done some searching but nothings come up yet</p>



<a name="133876851"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133876851" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133876851">(Sep 13 2018 at 11:14)</a>:</h4>
<p>no, sorry :/</p>



<a name="133876875"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133876875" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133876875">(Sep 13 2018 at 11:14)</a>:</h4>
<p>I could have sworn someone had suggested it as a future improvement and yet I cannot find a record of such discussion</p>



<a name="133876878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133876878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133876878">(Sep 13 2018 at 11:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ^</p>



<a name="133884806"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133884806" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133884806">(Sep 13 2018 at 13:37)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I don't understand what you mean</p>



<a name="133886246"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133886246" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133886246">(Sep 13 2018 at 13:59)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> I'm basically referring to my <a href="https://github.com/rust-lang/rust/issues/53528#issuecomment-420987614" target="_blank" title="https://github.com/rust-lang/rust/issues/53528#issuecomment-420987614">comment from 53528</a></p>



<a name="133886252"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133886252" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133886252">(Sep 13 2018 at 13:59)</a>:</h4>
<p>yeah, I had that impression</p>



<a name="133886255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133886255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133886255">(Sep 13 2018 at 13:59)</a>:</h4>
<p>(which now has its own topic)</p>



<a name="133886257"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/133886257" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#133886257">(Sep 13 2018 at 13:59)</a>:</h4>
<p>I read that afterwards and realized this must be the context</p>



<a name="134164409"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134164409" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134164409">(Sep 18 2018 at 12:58)</a>:</h4>
<p>Hmm, what am I missing here: <a href="https://play.rust-lang.org/?gist=5736ea474188c5a29de1257d790daf23&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=5736ea474188c5a29de1257d790daf23&amp;version=nightly&amp;mode=debug&amp;edition=2015">https://play.rust-lang.org/?gist=5736ea474188c5a29de1257d790daf23&amp;version=nightly&amp;mode=debug&amp;edition=2015</a></p>



<a name="134164425"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134164425" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134164425">(Sep 18 2018 at 12:58)</a>:</h4>
<p>OH</p>



<a name="134164428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134164428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134164428">(Sep 18 2018 at 12:58)</a>:</h4>
<p>So clever!</p>



<a name="134164439"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134164439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134164439">(Sep 18 2018 at 12:59)</a>:</h4>
<p>another mut borrow could come in!</p>



<a name="134164562"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134164562" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134164562">(Sep 18 2018 at 13:01)</a>:</h4>
<p>(and in fact even the Drop could happen. Oh that's such a great example. I wish the diagnostics for it were a tiny bit better</p>



<a name="134177539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134177539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134177539">(Sep 18 2018 at 16:42)</a>:</h4>
<p>it's a tricky example to explain</p>



<a name="134177586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134177586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134177586">(Sep 18 2018 at 16:42)</a>:</h4>
<p>particularly since <code>&amp;</code> borrows don't behave this way</p>



<a name="134322785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134322785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134322785">(Sep 20 2018 at 17:15)</a>:</h4>
<blockquote>
<p>nikomatsakis:<br>
<a href="#narrow/stream/122657-wg-nll/subject/weekly.20meeting.20September.2018/near/134190381" title="#narrow/stream/122657-wg-nll/subject/weekly.20meeting.20September.2018/near/134190381">it might be time to rejuvenate polonius then :)</a></p>
</blockquote>
<p>step 1: <a href="https://github.com/rust-lang-nursery/polonius/pull/77" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/77">make it build</a></p>



<a name="134325689"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134325689" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134325689">(Sep 20 2018 at 18:00)</a>:</h4>
<p>merged</p>



<a name="134325717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134325717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134325717">(Sep 20 2018 at 18:01)</a>:</h4>
<p>awesome, thank you niko</p>



<a name="134326438"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326438" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326438">(Sep 20 2018 at 18:13)</a>:</h4>
<p>Step 2: Get facts to work on nightly?</p>



<a name="134326455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326455">(Sep 20 2018 at 18:13)</a>:</h4>
<p>Step 3: profit ?</p>



<a name="134326708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326708">(Sep 20 2018 at 18:17)</a>:</h4>
<p>With any luck</p>



<a name="134326782"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326782" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326782">(Sep 20 2018 at 18:18)</a>:</h4>
<p>Step 3: get errors to work ;)</p>



<a name="134326800"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326800" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326800">(Sep 20 2018 at 18:19)</a>:</h4>
<p>there is at least one FIXME around facts and subtyping relationships</p>



<a name="134326803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326803">(Sep 20 2018 at 18:19)</a>:</h4>
<p>I forget what else I broke :P</p>



<a name="134326805"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326805" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326805">(Sep 20 2018 at 18:19)</a>:</h4>
<p>the way I would figure it out is probably to run the tests</p>



<a name="134326815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326815">(Sep 20 2018 at 18:19)</a>:</h4>
<p>move fast and break things, and all that</p>



<a name="134326826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134326826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134326826">(Sep 20 2018 at 18:19)</a>:</h4>
<p>or at least the second half, anyway</p>



<a name="134333694"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134333694" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134333694">(Sep 20 2018 at 20:08)</a>:</h4>
<p>Move faster than <code>./x.py build</code> at least</p>



<a name="134371794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134371794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134371794">(Sep 21 2018 at 11:26)</a>:</h4>
<p>step 1.1: <a href="https://github.com/rust-lang-nursery/polonius/pull/78" target="_blank" title="https://github.com/rust-lang-nursery/polonius/pull/78">make it a little faster</a></p>



<a name="134371807"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134371807" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134371807">(Sep 21 2018 at 11:27)</a>:</h4>
<p>gotchu <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> these were not integer steps :p</p>



<a name="134372418"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134372418" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134372418">(Sep 21 2018 at 11:41)</a>:</h4>
<p>Polonius will be so fast when we finally get it to work with rustc.</p>



<a name="134372862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134372862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134372862">(Sep 21 2018 at 11:53)</a>:</h4>
<p>I think there's also step 0. Decide what we want to do with polonius now that we don't have time constraints.</p>



<a name="134372865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134372865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134372865">(Sep 21 2018 at 11:53)</a>:</h4>
<p>faster, probably. "fast", maybe, let's hope so :)</p>



<a name="134372912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134372912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134372912">(Sep 21 2018 at 11:54)</a>:</h4>
<p>you have plot twisted the whole thing, these steps were not even positive floats</p>



<a name="134372933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134372933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134372933">(Sep 21 2018 at 11:55)</a>:</h4>
<p>jokes aside, yes agreed</p>



<a name="134379639"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134379639" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134379639">(Sep 21 2018 at 14:00)</a>:</h4>
<p>Step <code>NaN</code>; Step <code>+Inf</code></p>



<a name="134394954"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134394954" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134394954">(Sep 21 2018 at 18:17)</a>:</h4>
<p>Step <code>+inf</code>: borrowck is perfect.</p>



<a name="134397326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134397326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134397326">(Sep 21 2018 at 18:57)</a>:</h4>
<blockquote>
<p>I think there's also step 0. Decide what we want to do with polonius now that we don't have time constraints.</p>
</blockquote>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> what are you thinking of here?</p>



<a name="134398103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134398103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134398103">(Sep 21 2018 at 19:11)</a>:</h4>
<p>At least: 1. Do we want to move initializedness checks to Polonius as well</p>



<a name="134398138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134398138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134398138">(Sep 21 2018 at 19:11)</a>:</h4>
<p>2. How do we handle liveness, given that the current NLL implementation has to not calculate it for performance reasons.</p>



<a name="134399273"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134399273" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134399273">(Sep 21 2018 at 19:31)</a>:</h4>
<p>ah, yes. I think the answer to 1 is probably yes, but I'd probably rather wait until we get the rest up and going. </p>
<p>As for liveness, we are still computing it, we're doing it differently though. I don't think this matters much to polonius, actually, which doesn't have as much bias as to how the representation is setup.</p>
<p>The real question though is whether polonius will need to <em>grow</em> such a bias, since right now it just operates on pairs of tuples, but we're using bitsets for liveness at present. </p>
<p>Ideally, we'd move the liveness computation into polonius as well, I think</p>



<a name="134400648"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134400648" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134400648">(Sep 21 2018 at 19:57)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> we don't have to merge the previous PR quickly, you can take your time to review, when things are less hectic, and then iterate on it so that it is less hacky :)</p>



<a name="134402465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134402465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134402465">(Sep 21 2018 at 20:27)</a>:</h4>
<p>I'll wait for a time that is more suitable for the whole WG, to make polonius PRs, so we can all weigh in on what to do and how to do it best, without time constraints or pressure, and the end result will be better I'm sure</p>



<a name="134437331"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134437331" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134437331">(Sep 22 2018 at 13:17)</a>:</h4>
<p>PR for step2: <a href="https://github.com/rust-lang/rust/issues/54468" target="_blank" title="https://github.com/rust-lang/rust/issues/54468">#54468</a></p>



<a name="134450916"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134450916" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134450916">(Sep 22 2018 at 20:07)</a>:</h4>
<p>Is there  a way to get to (file,line,column) triplet from the BasicBlock structure ?</p>



<a name="134451171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134451171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134451171">(Sep 22 2018 at 20:15)</a>:</h4>
<p>Most likely you'll want to get a <code>Span</code>, and then get the error reporting functions to do the rest.</p>



<a name="134451220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134451220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134451220">(Sep 22 2018 at 20:17)</a>:</h4>
<p>So generally you want <code>self.mir.source_info(location).span</code></p>



<a name="134452332"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134452332" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134452332">(Sep 22 2018 at 20:57)</a>:</h4>
<p>Thanks a lot <span class="user-mention" data-user-id="116118">@Matthew Jasper</span></p>



<a name="134455067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134455067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134455067">(Sep 22 2018 at 22:34)</a>:</h4>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> <br>
one more question, <br>
```for moi in &amp;self.move_data.loc_map</p>
<div class="codehilite"><pre><span></span>How can I trace a move_out index back to line/column of code ?
</pre></div>



<a name="134455529"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134455529" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134455529">(Sep 22 2018 at 22:53)</a>:</h4>
<p>You can do</p>
<div class="codehilite"><pre><span></span><span class="kd">let</span><span class="w"> </span><span class="n">location</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">move_data</span><span class="p">.</span><span class="n">moves</span><span class="p">[</span><span class="o">*</span><span class="n">moi</span><span class="p">].</span><span class="n">source</span><span class="p">;</span><span class="w"></span>
<span class="kd">let</span><span class="w"> </span><span class="n">span</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="bp">self</span><span class="p">.</span><span class="n">mir</span><span class="p">.</span><span class="n">source_info</span><span class="p">(</span><span class="n">location</span><span class="p">).</span><span class="n">span</span><span class="p">;</span><span class="w"></span>
<span class="c1">// use span</span>
</pre></div>



<a name="134455725"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134455725" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134455725">(Sep 22 2018 at 23:00)</a>:</h4>
<p>From your reply in another thread, you do can just do <code>let span = self.mir.source_info(l).span;</code></p>



<a name="134456456"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134456456" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134456456">(Sep 22 2018 at 23:29)</a>:</h4>
<p>thanks <span class="user-mention" data-user-id="116118">@Matthew Jasper</span></p>



<a name="134456512"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134456512" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134456512">(Sep 22 2018 at 23:30)</a>:</h4>
<p>If I could also do <code>let span = self.mir.source_info(l).span</code> ?<br>
Then what happens if the location is not a move location ?</p>



<a name="134456566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134456566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> blitzerr <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134456566">(Sep 22 2018 at 23:32)</a>:</h4>
<p>I am only two weeks old in Rust; still getting my bearings right <span class="emoji emoji-1f642" title="slight smile">:slight_smile:</span></p>



<a name="134470127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134470127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134470127">(Sep 23 2018 at 08:07)</a>:</h4>
<p>If there's no move there then the for loop will be iterating over an empty list of moves, so nothing happens.</p>



<a name="134618426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134618426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134618426">(Sep 25 2018 at 18:44)</a>:</h4>
<blockquote>
<p>statementizing</p>
<p>new brain child</p>
</blockquote>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I hope these aren't words that make it into the diagnostic <span class="emoji emoji-1f609" title="wink">:wink:</span></p>



<a name="134618968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134618968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134618968">(Sep 25 2018 at 18:51)</a>:</h4>
<p>My goal is Miriam Webster!!</p>



<a name="134619526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134619526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134619526">(Sep 25 2018 at 18:59)</a>:</h4>
<p><a href="/user_uploads/4715/3nrXWH5tTqHBvkw7VTuSQl3d/statementize.png" target="_blank" title="statementize.png">statementize.png</a></p>
<div class="message_inline_image"><a href="/user_uploads/4715/3nrXWH5tTqHBvkw7VTuSQl3d/statementize.png" target="_blank" title="statementize.png"><img src="/user_uploads/4715/3nrXWH5tTqHBvkw7VTuSQl3d/statementize.png"></a></div>



<a name="134620061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134620061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134620061">(Sep 25 2018 at 19:07)</a>:</h4>
<p>I followed the link </p>
<p><a href="/user_uploads/4715/qTsdsEMn2SYR_M7bETx8xYUM/pasted_image.png" target="_blank" title="pasted_image.png">pasted image</a></p>
<div class="message_inline_image"><a href="/user_uploads/4715/qTsdsEMn2SYR_M7bETx8xYUM/pasted_image.png" target="_blank" title="pasted image"><img src="/user_uploads/4715/qTsdsEMn2SYR_M7bETx8xYUM/pasted_image.png"></a></div>



<a name="134730453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134730453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134730453">(Sep 27 2018 at 08:32)</a>:</h4>
<p>Anyone want to review PR <a href="https://github.com/rust-lang/rust/issues/54355" target="_blank" title="https://github.com/rust-lang/rust/issues/54355">#54355</a> ? Its "just" a regression test, and it got auto-assigned to aturon who is pretty swamped.</p>



<a name="134773125"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773125" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773125">(Sep 27 2018 at 20:53)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> is this a know issue with type checking?</p>
<div class="codehilite"><pre><span></span><span class="k">fn</span> <span class="nf">call2</span><span class="o">&lt;</span><span class="na">&#39;a</span><span class="p">,</span><span class="w"> </span><span class="na">&#39;b</span><span class="o">&gt;</span><span class="p">(</span><span class="n">a</span>: <span class="kp">&amp;</span><span class="na">&#39;a</span><span class="w"> </span><span class="kt">usize</span><span class="p">,</span><span class="w"> </span><span class="n">b</span>: <span class="kp">&amp;</span><span class="na">&#39;b</span><span class="w"> </span><span class="kt">usize</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">z</span>: <span class="nb">Option</span><span class="o">&lt;&amp;</span><span class="na">&#39;b</span><span class="w"> </span><span class="o">&amp;</span><span class="na">&#39;a</span><span class="w"> </span><span class="kt">usize</span><span class="o">&gt;</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">None</span><span class="p">;</span><span class="w"> </span><span class="c1">// Should error, don&#39;t know that &#39;a: &#39;b</span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="134773151"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773151" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773151">(Sep 27 2018 at 20:53)</a>:</h4>
<p>Hmm, we don't check the user annot for WF I guess.</p>



<a name="134773155"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773155" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773155">(Sep 27 2018 at 20:53)</a>:</h4>
<p>I feel like I did know about this</p>



<a name="134773156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773156">(Sep 27 2018 at 20:53)</a>:</h4>
<p>and had planned to fix it</p>



<a name="134773160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773160">(Sep 27 2018 at 20:54)</a>:</h4>
<p>but somehow it didn't happen</p>



<a name="134773161"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773161" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773161">(Sep 27 2018 at 20:54)</a>:</h4>
<p>file a bug?</p>



<a name="134773201"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773201" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773201">(Sep 27 2018 at 20:54)</a>:</h4>
<p>I can leave some notes on how to fix if you want to do so</p>



<a name="134773204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773204">(Sep 27 2018 at 20:54)</a>:</h4>
<p>and/or just give you a tip right now :)</p>



<a name="134773423"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134773423" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134773423">(Sep 27 2018 at 20:59)</a>:</h4>
<p>Opened <a href="https://github.com/rust-lang/rust/issues/54620" target="_blank" title="https://github.com/rust-lang/rust/issues/54620">#54620</a></p>



<a name="134812674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812674">(Sep 28 2018 at 09:38)</a>:</h4>
<p>Hey <span class="user-mention" data-user-id="116107">@davidtwco</span> , I'm doing some hacking that involves the <code>BorrowExplanation</code>s you added</p>



<a name="134812693"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812693" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812693">(Sep 28 2018 at 09:39)</a>:</h4>
<p>and I was thinking that the name <code>.emit</code> is a little unfortunate, because the error objects that we create already use the name <code>emit</code> to mean "issue this message to the stderr now please." (rather than say, buffering it)</p>



<a name="134812701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812701">(Sep 28 2018 at 09:40)</a>:</h4>
<p>So I wanted to know if you'd like to spend a moment now to help me bikeshed a different name?</p>



<a name="134812759"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812759" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812759">(Sep 28 2018 at 09:40)</a>:</h4>
<p>Sure.</p>



<a name="134812766"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812766" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812766">(Sep 28 2018 at 09:41)</a>:</h4>
<p>I think I experimented with  a handful of names (I'm unsure if the similar change I made in the <code>region_name</code> module used <code>emit</code> too).</p>



<a name="134812769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812769">(Sep 28 2018 at 09:41)</a>:</h4>
<p>So if I understand right, the current <code>BorrowExplanation::emit(&amp;self, tcx, err)</code> accumulates the explanation from <code>self</code> into <code>err</code></p>



<a name="134812787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812787">(Sep 28 2018 at 09:41)</a>:</h4>
<p>My first thought is "report"</p>



<a name="134812793"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812793" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812793">(Sep 28 2018 at 09:41)</a>:</h4>
<p>or even ... "explain" ?</p>



<a name="134812797"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812797" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812797">(Sep 28 2018 at 09:41)</a>:</h4>
<p>(but having an explanation explain seems goofy)</p>



<a name="134812798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812798">(Sep 28 2018 at 09:41)</a>:</h4>
<p><code>add_explanation_to_diagnostic</code></p>



<a name="134812799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812799">(Sep 28 2018 at 09:41)</a>:</h4>
<p>Hah!</p>



<a name="134812800"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812800" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812800">(Sep 28 2018 at 09:41)</a>:</h4>
<p>Definitely self explanatory</p>



<a name="134812801"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812801" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812801">(Sep 28 2018 at 09:41)</a>:</h4>
<p>I like it</p>



<a name="134812840"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812840" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812840">(Sep 28 2018 at 09:42)</a>:</h4>
<p>its not like this method name needs to be short</p>



<a name="134812849"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812849" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812849">(Sep 28 2018 at 09:42)</a>:</h4>
<p>Okay I'll throw that alpha-rename into what I'm doing.</p>



<a name="134812851"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812851" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812851">(Sep 28 2018 at 09:42)</a>:</h4>
<p>We should check the <code>region_name</code> module to see if it uses <code>emit</code> too - we might want to change that there too?</p>



<a name="134812854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812854">(Sep 28 2018 at 09:42)</a>:</h4>
<p>I'll look quickly</p>



<a name="134812867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812867">(Sep 28 2018 at 09:42)</a>:</h4>
<p>Ah, no, I used <code>highlight_region_name</code> in that case.</p>



<a name="134812871"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812871" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812871">(Sep 28 2018 at 09:42)</a>:</h4>
<p>great</p>



<a name="134812872"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812872" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812872">(Sep 28 2018 at 09:42)</a>:</h4>
<p>Also, before I waste time finding out</p>



<a name="134812886"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812886" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812886">(Sep 28 2018 at 09:43)</a>:</h4>
<p>was there any reason you didn't (or couldn't) send the <code>mir</code> along into the <code>emit</code> (aka <code>add_explanation_to_diagnostic</code>) method when you call it?</p>



<a name="134812896"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812896" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812896">(Sep 28 2018 at 09:43)</a>:</h4>
<p>Didn't need it to do what the function did.</p>



<a name="134812898"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812898" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812898">(Sep 28 2018 at 09:43)</a>:</h4>
<p>Okay</p>



<a name="134812942"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812942" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812942">(Sep 28 2018 at 09:44)</a>:</h4>
<p>The reason I ask <em>that</em> is that I'm adding a variant that corresponds to  "Dropping an unnamed temporary"</p>



<a name="134812945"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812945" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812945">(Sep 28 2018 at 09:44)</a>:</h4>
<p>and I can either have the variant carry all the spans I'm interested in</p>



<a name="134812951"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812951" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812951">(Sep 28 2018 at 09:44)</a>:</h4>
<p>or I could have it just carry the <code>mir::Local</code></p>



<a name="134812955"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812955" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812955">(Sep 28 2018 at 09:44)</a>:</h4>
<p>I tried to do all of the logic that would need that in creating the <code>BorrowExplanation</code> - leaving just a couple spans and messages left. It was really just a mechanism so I could selectively choose not to emit certain types of explanations.</p>



<a name="134812961"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812961" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812961">(Sep 28 2018 at 09:44)</a>:</h4>
<p>(sorry, "just the <code>mir::Local</code> and the <code>Location</code>, I think...)</p>



<a name="134812973"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812973" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812973">(Sep 28 2018 at 09:45)</a>:</h4>
<p>Hmm, interesting</p>



<a name="134812987"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134812987" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134812987">(Sep 28 2018 at 09:45)</a>:</h4>
<p>So your thought is that the <code>add_explanation_to_diagnostic</code> should itself not do much extraction of the spans ?</p>



<a name="134813060"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813060" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813060">(Sep 28 2018 at 09:46)</a>:</h4>
<p>My intent when adding it was that it kept just what it needed to add a message to a diagnostic and that the <code>explain_borrow</code> function that creates it does all the working that out. If you think it makes more sense for it to do more, then feel free to change it though.</p>



<a name="134813069"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813069" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813069">(Sep 28 2018 at 09:46)</a>:</h4>
<p>Okay I'll play around with it</p>



<a name="134813072"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813072" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813072">(Sep 28 2018 at 09:47)</a>:</h4>
<p>thanks!</p>



<a name="134813083"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813083" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813083">(Sep 28 2018 at 09:47)</a>:</h4>
<p>I figured that in 99% of cases, the explanation would have <code>add_explaination_to_diagnostic</code> called almost immediately after being created anyway - as it was previously. But for the PR I added it in, I wanted to be able to say "add to the diagnostic unless your explanation is X, that isn't helpful now"</p>



<a name="134813531"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813531" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813531">(Sep 28 2018 at 09:54)</a>:</h4>
<p>I didn't even notice the indentation <span class="emoji emoji-1f926" title="face palm">:face_palm:</span></p>



<a name="134813664"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813664" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813664">(Sep 28 2018 at 09:57)</a>:</h4>
<p>its easy to miss</p>



<a name="134813675"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813675" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813675">(Sep 28 2018 at 09:58)</a>:</h4>
<p>(maybe auto-running <code>rustfmt</code> as part of bors isn't such a crazy idea after all...)</p>



<a name="134813720"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813720" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813720">(Sep 28 2018 at 09:58)</a>:</h4>
<p>(at least having tidy run <code>rustfmt --write-mode diff</code> would have spotted it)</p>



<a name="134813736"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813736" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813736">(Sep 28 2018 at 09:58)</a>:</h4>
<p>/me didn't even know about <code>rustfmt --write-mode diff</code> ...</p>



<a name="134813751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813751">(Sep 28 2018 at 09:59)</a>:</h4>
<p>I have <em>got</em> to put some time aside to better acquaint myself with the various tools in the Rust ecosystem</p>



<a name="134813756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813756">(Sep 28 2018 at 09:59)</a>:</h4>
<p>I only just today learned about the <code>-W</code> option to <code>git log --patch</code></p>



<a name="134813944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813944">(Sep 28 2018 at 10:03)</a>:</h4>
<p>And now I have.</p>



<a name="134813950"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134813950" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134813950">(Sep 28 2018 at 10:03)</a>:</h4>
<p><a href="https://xkcd.com/1053/" target="_blank" title="https://xkcd.com/1053/">https://xkcd.com/1053/</a></p>



<a name="134814050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814050">(Sep 28 2018 at 10:05)</a>:</h4>
<p>I think I need to do something structured about this problem. Like, maybe plan to write a short blog post per week (or maybe per day?!?) discussing a "favorite tool" or even "favorite option/flag/mode" for a tool</p>



<a name="134814102"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814102" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814102">(Sep 28 2018 at 10:06)</a>:</h4>
<p>It would be good to get in the habit of writing in a structured manner like that again. My previous blog posts were all so epic that it became daunting to attempt a new one..</p>



<a name="134814104"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814104" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814104">(Sep 28 2018 at 10:07)</a>:</h4>
<p>(and thus I haven't posted in <em>literally</em> years....)</p>



<a name="134814475"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814475" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814475">(Sep 28 2018 at 10:15)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span>  you need to finish your series on GCs :)</p>



<a name="134814477"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814477" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814477">(Sep 28 2018 at 10:15)</a>:</h4>
<p>it was Good ™</p>



<a name="134814520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814520">(Sep 28 2018 at 10:16)</a>:</h4>
<p>yeah. There was rumblings of maybe having me resume looking at GC stuff again</p>



<a name="134814524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814524">(Sep 28 2018 at 10:16)</a>:</h4>
<p>Once the edition's out, we'll see</p>



<a name="134814537"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814537" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814537">(Sep 28 2018 at 10:17)</a>:</h4>
<p>with josephine, and apparently Stephen Dolan's rust+ocaml shindig, the landscape has a bit changed since then as well</p>



<a name="134814548"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814548" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814548">(Sep 28 2018 at 10:17)</a>:</h4>
<p>and WASM is also a significant part of the picture</p>



<a name="134814591"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134814591" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134814591">(Sep 28 2018 at 10:18)</a>:</h4>
<p>hopefully they move on with their GC / host binding plans soon indeed</p>



<a name="134993128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134993128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134993128">(Oct 01 2018 at 20:03)</a>:</h4>
<p>dtolnay found a nll ICE this morning. the issue appears to be more about lifetime inference than nll, but tagged/linking if it's worth being on radar <a href="https://github.com/rust-lang/rust/issues/54124" target="_blank" title="https://github.com/rust-lang/rust/issues/54124">https://github.com/rust-lang/rust/issues/54124</a></p>



<a name="134993697"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134993697" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134993697">(Oct 01 2018 at 20:12)</a>:</h4>
<p>is it <a href="https://github.com/rust-lang/rust/issues/53420" target="_blank" title="https://github.com/rust-lang/rust/issues/53420">#53420</a> / <a href="https://play.rust-lang.org/?gist=5fba8c5e897ef55e730008fb6ebdb0b2&amp;version=stable&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.rust-lang.org/?gist=5fba8c5e897ef55e730008fb6ebdb0b2&amp;version=stable&amp;mode=debug&amp;edition=2015">playground</a> ?</p>



<a name="134993985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134993985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134993985">(Oct 01 2018 at 20:17)</a>:</h4>
<p>oh yea, those are incredibly similar, except the one using PhantomData doesn't ICE on 2015 or 2018 without explictly adding <code>#![feature(nll)]</code></p>



<a name="134994053"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134994053" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryruins <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134994053">(Oct 01 2018 at 20:18)</a>:</h4>
<p>but nearly the same code sample</p>



<a name="134996182"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/134996182" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#134996182">(Oct 01 2018 at 20:58)</a>:</h4>
<p>left some comments</p>



<a name="135042029"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135042029" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135042029">(Oct 02 2018 at 15:05)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> in <a href="https://github.com/rust-lang/rust/issues/21232#issuecomment-426290385" target="_blank" title="https://github.com/rust-lang/rust/issues/21232#issuecomment-426290385">https://github.com/rust-lang/rust/issues/21232#issuecomment-426290385</a>, do you mean to say "Our current status <strong>in Rust 2018 / with NLL</strong>"?</p>



<a name="135042122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135042122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135042122">(Oct 02 2018 at 15:06)</a>:</h4>
<p>Because the <a href="https://play.integer32.com/?gist=3f8414e24598551b9a8c2ed231d1aec4&amp;version=stable&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.integer32.com/?gist=3f8414e24598551b9a8c2ed231d1aec4&amp;version=stable&amp;mode=debug&amp;edition=2015">first example you gave doesn't compile pre-NLL</a></p>



<a name="135042671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135042671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135042671">(Oct 02 2018 at 15:16)</a>:</h4>
<p>right, you have to use the variant that moves <code>s</code> away. I'll fix it.</p>



<a name="135042969"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135042969" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135042969">(Oct 02 2018 at 15:21)</a>:</h4>
<p>oh actually, it suffices to just declare <code>s</code> as <code>mut</code>.</p>



<a name="135043076"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043076" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043076">(Oct 02 2018 at 15:23)</a>:</h4>
<p>Yep, which is a change from pre- / post- NLL too</p>



<a name="135043350"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043350" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043350">(Oct 02 2018 at 15:28)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> I don't understand: it seems to me like NLL <em>also</em> <a href="https://play.integer32.com/?gist=d6bc9d86d5e8694576e3fa0e5f62de76&amp;version=nightly&amp;mode=debug&amp;edition=2015" target="_blank" title="https://play.integer32.com/?gist=d6bc9d86d5e8694576e3fa0e5f62de76&amp;version=nightly&amp;mode=debug&amp;edition=2015">requires</a> you declare <code>s</code> as <code>mut</code>?</p>



<a name="135043379"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043379" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043379">(Oct 02 2018 at 15:28)</a>:</h4>
<p>(which might not be something we stick to in the long term; but I'm not yet seeing the change in behavior you are referencing in this particular case)</p>



<a name="135043401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043401">(Oct 02 2018 at 15:29)</a>:</h4>
<p>I do know that the unused_mut lint is broken for this case</p>



<a name="135043403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043403">(Oct 02 2018 at 15:29)</a>:</h4>
<p>(for NLL)</p>



<a name="135043407"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043407" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043407">(Oct 02 2018 at 15:29)</a>:</h4>
<p>which may well be an instance of <a href="https://github.com/rust-lang/rust/issues/54586" target="_blank" title="https://github.com/rust-lang/rust/issues/54586">#54586</a></p>



<a name="135043414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043414">(Oct 02 2018 at 15:29)</a>:</h4>
<p>Oh, I was just assuming that your original code worked and that you were testing it in a different context than "stable"</p>



<a name="135043426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043426">(Oct 02 2018 at 15:29)</a>:</h4>
<p>no i was just writing without testing. :)</p>



<a name="135043511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135043511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135043511">(Oct 02 2018 at 15:30)</a>:</h4>
<p>I was adding the comment to the other commenter showing that <code>let s: i32; s = 42</code> works today, but when I tried with a struct I got the "needs mut" error, which is the only reason I caught it in your comment</p>



<a name="135129532"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129532" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129532">(Oct 03 2018 at 20:03)</a>:</h4>
<p>does Rust tests has some kind of interruption that makes the current output to be displayed?</p>



<a name="135129546"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129546" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129546">(Oct 03 2018 at 20:03)</a>:</h4>
<p>so you don't need to wait until the whole thing finished to see the current failures output</p>



<a name="135129597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129597">(Oct 03 2018 at 20:04)</a>:</h4>
<p>I remember that minitest in Ruby handled ctrl+t in that way</p>



<a name="135129627"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129627" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129627">(Oct 03 2018 at 20:05)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>, others? <span class="emoji emoji-261d" title="point of information">:point_of_information:</span></p>



<a name="135129642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129642">(Oct 03 2018 at 20:05)</a>:</h4>
<blockquote>
<p>does Rust tests has some kind of interruption that makes the current output to be displayed?</p>
</blockquote>
<p>I guess you mean the <code>x.py test</code> stuff?</p>



<a name="135129654"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129654" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129654">(Oct 03 2018 at 20:05)</a>:</h4>
<p>There's <code>cargo test -- --nocapture</code></p>



<a name="135129756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129756">(Oct 03 2018 at 20:07)</a>:</h4>
<blockquote>
<blockquote>
<p>does Rust tests has some kind of interruption that makes the current output to be displayed?</p>
</blockquote>
<p>I guess you mean the <code>x.py test</code> stuff?</p>
</blockquote>
<p>yep</p>



<a name="135129763"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129763" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129763">(Oct 03 2018 at 20:07)</a>:</h4>
<p>I think verbose-tests  in config.toml might be doing that, it's IIRC how CI runs them, and it always shows them line by line, so I assume also with errors</p>



<a name="135129768"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129768" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129768">(Oct 03 2018 at 20:07)</a>:</h4>
<p>well the <code>-- --nocapture</code> could work if can be passed to <code>x.py</code></p>



<a name="135129855"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129855" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129855">(Oct 03 2018 at 20:09)</a>:</h4>
<p>I think you may want to tweak your config.toml</p>



<a name="135129883"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129883" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129883">(Oct 03 2018 at 20:09)</a>:</h4>
<p>as <span class="user-mention" data-user-id="116113">@lqd</span> said, there is this setting:</p>
<div class="codehilite"><pre><span></span># Suppresses extraneous output from tests to ensure the output of the test
# harness is relatively clean.
#quiet-tests = true
</pre></div>



<a name="135129893"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129893" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129893">(Oct 03 2018 at 20:09)</a>:</h4>
<p>I think if it is false, you get more interactive output</p>



<a name="135129995"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129995" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129995">(Oct 03 2018 at 20:11)</a>:</h4>
<p>ahhh ok ok</p>



<a name="135129996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135129996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135129996">(Oct 03 2018 at 20:11)</a>:</h4>
<p>cool</p>



<a name="135130064"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135130064" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135130064">(Oct 03 2018 at 20:12)</a>:</h4>
<p>also responding to signals in a cross-platform, multi-threaded safe way is amazingly annoying</p>



<a name="135130067"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135130067" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135130067">(Oct 03 2018 at 20:12)</a>:</h4>
<p>(it might be necessary to also nuke the built tests though)</p>



<a name="135132949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135132949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135132949">(Oct 03 2018 at 20:50)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> I don't see <code>quiet-tests</code> on the generated config.toml.example file</p>



<a name="135132954"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135132954" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135132954">(Oct 03 2018 at 20:50)</a>:</h4>
<p>is that correct?</p>



<a name="135132981"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135132981" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135132981">(Oct 03 2018 at 20:51)</a>:</h4>
<p>ahh probably this ...</p>



<a name="135132984"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135132984" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135132984">(Oct 03 2018 at 20:51)</a>:</h4>
<div class="codehilite"><pre><span></span># Emits extraneous output from tests to ensure that failures of the test
# harness are debuggable just from logfiles.
#verbose-tests = false
</pre></div>



<a name="135133171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135133171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135133171">(Oct 03 2018 at 20:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> ah probably changed yeah</p>



<a name="135133173"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135133173" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135133173">(Oct 03 2018 at 20:55)</a>:</h4>
<p>since my config.toml was copie</p>



<a name="135133342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135133342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135133342">(Oct 03 2018 at 20:59)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> yeah that's the one I mentioned earlier :)</p>



<a name="135133429"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135133429" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135133429">(Oct 03 2018 at 21:00)</a>:</h4>
<p><span class="emoji emoji-1f44d" title="+1">:+1:</span></p>



<a name="135133476"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135133476" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135133476">(Oct 03 2018 at 21:01)</a>:</h4>
<p>Felix and I used it recently when looking for the weird CI error we couldn't reproduce, I haven't seen it fail so I only can assume it does what you want (and what CI does) but I've seen it switch from using the block ...II..FF to line by line so it should work</p>



<a name="135234826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135234826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135234826">(Oct 05 2018 at 05:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> here is an interesting temo  r-value lifetime oddity I was previously unaware of: <a href="https://github.com/rust-lang/rust/issues/21114#issuecomment-426963631" target="_blank" title="https://github.com/rust-lang/rust/issues/21114#issuecomment-426963631">https://github.com/rust-lang/rust/issues/21114#issuecomment-426963631</a></p>



<a name="135241214"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135241214" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135241214">(Oct 05 2018 at 08:20)</a>:</h4>
<p>*"temp", not "temo"</p>



<a name="135261587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135261587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135261587">(Oct 05 2018 at 15:25)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> I believe that was quite intentional: whenever there is "conditional flow", temporaries cannot escape it. It's obvious that this makes sense for loops (to prevent unbounded buildup). I'm not sure if it was <em>necessary</em> for if/else but...</p>



<a name="135262089"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262089" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262089">(Oct 05 2018 at 15:33)</a>:</h4>
<p>I certainly would understand if the temps in the <em>test condition</em> died early</p>



<a name="135262099"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262099" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262099">(Oct 05 2018 at 15:33)</a>:</h4>
<p>I think they do, too</p>



<a name="135262168"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262168" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262168">(Oct 05 2018 at 15:34)</a>:</h4>
<p>regardless, I dont' think we can/should change the rules here at the moment, right?</p>



<a name="135262173"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262173" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262173">(Oct 05 2018 at 15:34)</a>:</h4>
<p>But the tail of the then/else blocks strike me as analogous to “tail position”, when thinking about the space-efficiency semantics</p>



<a name="135262175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262175">(Oct 05 2018 at 15:34)</a>:</h4>
<p>i.e., didn't we rule that out of scope without careful evaluation etc?</p>



<a name="135262195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262195">(Oct 05 2018 at 15:35)</a>:</h4>
<p>No I  don’t think we can change the rules in time for 2018 edition</p>



<a name="135262204"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262204" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262204">(Oct 05 2018 at 15:35)</a>:</h4>
<p>Just wanted to note it</p>



<a name="135262208"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262208" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262208">(Oct 05 2018 at 15:35)</a>:</h4>
<p>Since it led people to make interestign bugs</p>



<a name="135262253"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135262253" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135262253">(Oct 05 2018 at 15:36)</a>:</h4>
<p>k</p>



<a name="135386714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135386714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135386714">(Oct 08 2018 at 08:05)</a>:</h4>
<p>(I will be having little free time in the coming weeks because of $dayjob, so if I'm less active/available for the foreseeable future, this will be why)</p>



<a name="135471612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135471612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135471612">(Oct 09 2018 at 14:02)</a>:</h4>
<p>Hey <span class="user-mention" data-user-id="116107">@davidtwco</span> do you have any opinion on how the intermediate buffering/filtering/sorting done by the <code>move_error_reported</code> BTreeMap should interact with <code>-Z dont-buffer-diagnostics</code> and, perhaps more importantly, <code>-Z treat-err-as-bug</code> ?</p>



<a name="135471657"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135471657" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135471657">(Oct 09 2018 at 14:03)</a>:</h4>
<p>right now the <code>move_error_reported</code> intermediate map sort of messes up the workflow of using <code>-Z treat-err-as-bug</code> to get stack traces that point right to the place where the error was generated. But its also not clear to me whether it makes sense to adopt the strategy of immediately emitting such errors when those <code>-Z</code> flags are present, since the errors in question might end up getting suppressed down the road</p>



<a name="135472003"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472003" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472003">(Oct 09 2018 at 14:09)</a>:</h4>
<p>Hmm,  I'm not sure. Having an error fire straight away wouldn't work because, like you said, it might have ended up being suppressed. </p>
<p>w/r/t <code>-Z dont-buffer-diagnostics</code>, I think we consider the location where the errors are currently loaded into the buffer as the place where they should be emitted since otherwise we get the normally suppressed errors being emitted and that's not useful. </p>
<p>w/r/t <code>-Z treat-err-as-bug</code>, the <code>move_error_reported</code> map really messes this up. I believe there are like four maps/sets that are used to deduplicate errors but that particular one is the only one that doesn't just keep the first error IIRC. </p>
<p>In a previous PR, I added a <code>debug!</code> log to <code>rustc_errors</code> when a diagnostic is buffered so that I can find it in <code>RUST_LOG</code> output and get some idea of where it is in the compiler from the surrounding logs.</p>



<a name="135472384"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472384" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472384">(Oct 09 2018 at 14:15)</a>:</h4>
<p>I'm sort of tempted to try to generalize <code>-Z treat-err-as-bug</code> to take an optional argument. Or add a <code>-Z treat-nth-err-as-bug=&lt;N&gt;</code> and then that would cause a panic on the N'th <code>emit()</code> call</p>



<a name="135472409"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472409" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472409">(Oct 09 2018 at 14:15)</a>:</h4>
<p>Unless there's some way that I'm not aware of to save the backtrace when we're buffering those errors so that we can error later with that backtrace (and I expect that this isn't possible), I'm not sure there's a nice way to have that interaction work.</p>



<a name="135472500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472500">(Oct 09 2018 at 14:16)</a>:</h4>
<p>(a <code>-Z treat-nth-err-as-bug=&lt;N&gt;</code> flag wouldn't be enough on its own... I'm just musing whether its a necessity, if one wants to have any chance of debugging an error that arises <em>after</em> another error has been emitted ...)</p>



<a name="135472527"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472527" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472527">(Oct 09 2018 at 14:17)</a>:</h4>
<p>I think we <em>could</em> save a backtrace. I don't know whether we <strong>should</strong>...</p>



<a name="135472548"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472548" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472548">(Oct 09 2018 at 14:17)</a>:</h4>
<p>after all, my memory is that the <code>RUST_BACKTRACE</code> support is itself implemented in Rust...</p>



<a name="135472553"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472553" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472553">(Oct 09 2018 at 14:17)</a>:</h4>
<p>I suppose it wouldn't be possible to disable the deduplication in that case and get all of the errors, each with stack traces?</p>



<a name="135472615"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472615" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472615">(Oct 09 2018 at 14:18)</a>:</h4>
<p>With a <code>warning: some errors might be deduplicated when rustc is run without this flag</code> or something.</p>



<a name="135472621"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472621" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472621">(Oct 09 2018 at 14:18)</a>:</h4>
<blockquote>
<p>I suppose it wouldn't be possible to disable the deduplication in that case and get all of the errors, each with stack traces?</p>
</blockquote>
<p>Yeah this might be the more principled approach</p>



<a name="135472670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135472670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135472670">(Oct 09 2018 at 14:19)</a>:</h4>
<p>The errors, as far as I can remember, were never the same, so it should be possible to ignore the ones that weren't showing up for the test case before adding that flag.</p>



<a name="135533796"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135533796" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135533796">(Oct 10 2018 at 11:06)</a>:</h4>
<p>Does anyone object to me removing <a href="https://github.com/rust-lang/rust/issues/53114" target="_blank" title="https://github.com/rust-lang/rust/issues/53114">#53114</a> from the RC 2 milestone (we have parity with AST borrowck)</p>



<a name="135543545"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135543545" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135543545">(Oct 10 2018 at 14:11)</a>:</h4>
<p>I do not</p>



<a name="135589157"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135589157" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135589157">(Oct 11 2018 at 06:24)</a>:</h4>
<p>is there a tracking issue for this? <a href="https://play.rust-lang.org/?gist=76a259242ade7730cbc0a5ad7b68c360&amp;version=nightly&amp;mode=debug&amp;edition=2018" target="_blank" title="https://play.rust-lang.org/?gist=76a259242ade7730cbc0a5ad7b68c360&amp;version=nightly&amp;mode=debug&amp;edition=2018">https://play.rust-lang.org/?gist=76a259242ade7730cbc0a5ad7b68c360&amp;version=nightly&amp;mode=debug&amp;edition=2018</a></p>



<a name="135589322"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135589322" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135589322">(Oct 11 2018 at 06:29)</a>:</h4>
<p>the <code>x.get_mut(x.len())</code> is IMO a wrong error, even though it's going through a deref to get the method on slice</p>



<a name="135596156"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596156" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596156">(Oct 11 2018 at 09:16)</a>:</h4>
<p><span class="user-mention" data-user-id="116108">@Keith Yeung</span> my first guess is that this represents a limitation of our current implementation of two-phase borrows</p>



<a name="135596183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596183">(Oct 11 2018 at 09:17)</a>:</h4>
<p>i.e. I think you've hit the nail on the head: I bet the need to go through the deref is causing the mutable borrow to be activated "earlier" than you would have hoped.</p>



<a name="135596569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596569">(Oct 11 2018 at 09:24)</a>:</h4>
<p>But I do agree we should at least make sure this tracked somewhere</p>



<a name="135596634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596634">(Oct 11 2018 at 09:25)</a>:</h4>
<p>There are a couple different candidate issues where one might consider filing this</p>



<a name="135596682"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596682">(Oct 11 2018 at 09:26)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/44100" target="_blank" title="https://github.com/rust-lang/rust/issues/44100">#44100</a> is the most obvious to me. But it was closed in favor of <a href="https://github.com/rust-lang/rust/issues/43234" target="_blank" title="https://github.com/rust-lang/rust/issues/43234">#43234</a></p>



<a name="135596707"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596707" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596707">(Oct 11 2018 at 09:26)</a>:</h4>
<p>There are also some issues discussing expanding/generalizing two-phase borrows, namely <a href="https://github.com/rust-lang/rust/issues/51915" target="_blank" title="https://github.com/rust-lang/rust/issues/51915">#51915</a> and <a href="https://github.com/rust-lang/rust/issues/49434" target="_blank" title="https://github.com/rust-lang/rust/issues/49434">#49434</a></p>



<a name="135596723"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135596723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135596723">(Oct 11 2018 at 09:27)</a>:</h4>
<p>The other option is that we could just file an issue specifically about this particular case</p>



<a name="135715718"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135715718" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135715718">(Oct 13 2018 at 03:45)</a>:</h4>
<p>i've written a comment on <a href="https://github.com/rust-lang/rust/issues/49434" target="_blank" title="https://github.com/rust-lang/rust/issues/49434">#49434</a> which describes the problem</p>



<a name="135904413"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904413" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904413">(Oct 16 2018 at 14:41)</a>:</h4>
<p>Hey <span class="user-mention" data-user-id="116009">@nikomatsakis</span> , do you know offhand if the const-evaluator (or whatever system we use for compiling the RHS of statics) will generate different MIR depending on whether NLL is enabled or not?</p>



<a name="135904781"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904781" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904781">(Oct 16 2018 at 14:46)</a>:</h4>
<p>well</p>



<a name="135904787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904787">(Oct 16 2018 at 14:46)</a>:</h4>
<p>it starts from MIR construction</p>



<a name="135904790"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904790" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904790">(Oct 16 2018 at 14:46)</a>:</h4>
<p>so to the extent that MIR construction differs, it will</p>



<a name="135904811"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904811" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904811">(Oct 16 2018 at 14:46)</a>:</h4>
<p>I think this is largely confined to matches right now?</p>



<a name="135904861"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904861" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904861">(Oct 16 2018 at 14:47)</a>:</h4>
<p>hmm okay</p>



<a name="135904927"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/135904927" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#135904927">(Oct 16 2018 at 14:49)</a>:</h4>
<p>(I'm trying to puzzle out the difference in behavior between the 2015 and 2018 editions on <a href="https://github.com/rust-lang/rust/issues/54797" target="_blank" title="https://github.com/rust-lang/rust/issues/54797">#54797</a> )</p>



<a name="136366587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136366587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136366587">(Oct 23 2018 at 20:54)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> do you think you'd have time to review <a href="https://github.com/rust-lang/rust/pull/55150" target="_blank" title="https://github.com/rust-lang/rust/pull/55150">https://github.com/rust-lang/rust/pull/55150</a> ? Its small. But its a patch to AST-borrowck. (or rather, mem_categorization)</p>



<a name="136366633"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136366633" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136366633">(Oct 23 2018 at 20:55)</a>:</h4>
<p>(and I think if we don't get it in for RC2, then it may be worth beta-nomination)</p>



<a name="136366698"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136366698" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136366698">(Oct 23 2018 at 20:56)</a>:</h4>
<p>ok</p>



<a name="136366739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136366739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136366739">(Oct 23 2018 at 20:57)</a>:</h4>
<p>oh I guess <code>#[thread_local]</code> is not stabilized. so not worth beta-nomination in any circumstance</p>



<a name="136366750"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136366750" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136366750">(Oct 23 2018 at 20:57)</a>:</h4>
<p>(I kept forgetting why this wasn't higher priority for me to get someone to review)</p>



<a name="136496019"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136496019" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136496019">(Oct 25 2018 at 18:07)</a>:</h4>
<blockquote>
<p>I think Polonius is such a great name for that project. For those who didn't read Shakespeare's Hamlet, Polonius is known for giving the advice "Neither a borrower nor a lender be."</p>
</blockquote>



<a name="136496022"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136496022" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136496022">(Oct 25 2018 at 18:07)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> ^ someone got it ;-)</p>



<a name="136496076"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/136496076" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#136496076">(Oct 25 2018 at 18:08)</a>:</h4>
<p><span class="emoji emoji-1f389" title="tada">:tada:</span></p>



<a name="147850803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/147850803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#147850803">(Nov 16 2018 at 22:31)</a>:</h4>
<p>i just got a github notification informing me that i've been added to rust-lang/compiler-team</p>



<a name="147850810"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/147850810" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#147850810">(Nov 16 2018 at 22:31)</a>:</h4>
<p>did anyone receive the same notification?</p>



<a name="147850887"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/147850887" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#147850887">(Nov 16 2018 at 22:32)</a>:</h4>
<p>I think it's a because a new repository was created, anyone in the rust-lang org gets automatically subscribed.</p>



<a name="147850894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/147850894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Keith Yeung <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#147850894">(Nov 16 2018 at 22:32)</a>:</h4>
<p>ah</p>



<a name="150919450"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/150919450" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#150919450">(Dec 05 2018 at 11:03)</a>:</h4>
<p><span class="emoji emoji-1f438" title="frog">:frog:</span> 1.0 <span class="emoji emoji-1f389" title="tada">:tada:</span></p>



<a name="151012880"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151012880" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151012880">(Dec 06 2018 at 15:08)</a>:</h4>
<p>What happened to compare mode NLL? It doesn't get run by default in the UI suite unless I pass the <code>--compare-mode</code> flag now.</p>



<a name="151012916"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151012916" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151012916">(Dec 06 2018 at 15:09)</a>:</h4>
<p>Is it some side effect of the change to disable it on Windows to speed up CI?</p>



<a name="151012949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151012949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151012949">(Dec 06 2018 at 15:09)</a>:</h4>
<p>(note, not on Windows, well, I'm ssh'd into a Arch server from Windows, but I doubt x.py has figured that out)</p>



<a name="151013016"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151013016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> kennytm <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151013016">(Dec 06 2018 at 15:10)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/56391" target="_blank" title="https://github.com/rust-lang/rust/issues/56391">#56391</a></p>



<a name="151013047"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151013047" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> kennytm <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151013047">(Dec 06 2018 at 15:10)</a>:</h4>
<p>it is disabled by default and only enabled on <code>x86_64-gnu-nopt</code> now.</p>



<a name="151013053"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151013053" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151013053">(Dec 06 2018 at 15:10)</a>:</h4>
<p>Ah, I assumed that change would have only applied to the CI and the default on dev machines would remain the same.</p>



<a name="151013070"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151013070" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151013070">(Dec 06 2018 at 15:11)</a>:</h4>
<p>Thanks, I'll update my <code>config.toml</code>.</p>



<a name="151038423"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151038423" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151038423">(Dec 06 2018 at 19:57)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span> (and other contributors of course) congrats on shipping NLL to the world <span class="emoji emoji-1f389" title="tada">:tada:</span> you've done it! Thanks for all the hard work and talent and countless other things <span class="emoji emoji-1f44f" title="clap">:clap:</span></p>



<a name="151046291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151046291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151046291">(Dec 06 2018 at 21:46)</a>:</h4>
<p>everyone, as some people know I'm organizing Rust Latam and we have opened the cfp</p>



<a name="151046293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151046293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151046293">(Dec 06 2018 at 21:46)</a>:</h4>
<p><a href="https://cfp.rustlatam.org/events/rust-latam" target="_blank" title="https://cfp.rustlatam.org/events/rust-latam">https://cfp.rustlatam.org/events/rust-latam</a></p>



<a name="151046309"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151046309" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151046309">(Dec 06 2018 at 21:47)</a>:</h4>
<p>it would be nice if someone from this group want to send a proposal and maybe, why not, talk about the process of building NLL or something else that you want :)</p>



<a name="151046380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151046380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151046380">(Dec 06 2018 at 21:48)</a>:</h4>
<p>/cc <span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span></p>



<a name="151100879"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151100879" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151100879">(Dec 07 2018 at 10:10)</a>:</h4>
<blockquote>
<p>it would be nice if someone from this group want to send a proposal and maybe, why not, talk about the process of building NLL or something else that you want :)</p>
</blockquote>
<p>I love that idea</p>



<a name="151440530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151440530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151440530">(Dec 11 2018 at 11:56)</a>:</h4>
<p>We probably should have advertised this PR (and how to "undo" its effects locally) quite a bit more within this WG: <a href="https://github.com/rust-lang/rust/issues/56391" target="_blank" title="https://github.com/rust-lang/rust/issues/56391">#56391</a> "ci: Only run compare-mode tests on one builder"</p>



<a name="151440547"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/151440547" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#151440547">(Dec 11 2018 at 11:57)</a>:</h4>
<p>because its phrased as if it only affects the ci system, but I think its better phrased as a global effect (especially to us) that is undone on a single ci builder, I think.</p>



<a name="152298970"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152298970" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152298970">(Dec 21 2018 at 00:42)</a>:</h4>
<p>I've forgotten, looking at mir dumps, how do we map back from inference variables (I think it's their name, eg  _#1r) to named lifetimes again ? I'm not sure where to look in the mir dump (I wanted to check and generate NLL facts so I wanted to verify if a specific free region in the source was present in the facts)</p>



<a name="152323117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323117">(Dec 21 2018 at 11:05)</a>:</h4>
<p>I don't know if the current mir dumps include that info. I would have expected to see it somewhere in the <code>*.nll.0.mir</code> dump, but I don't see it in one I have handy here.</p>



<a name="152323140"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323140" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323140">(Dec 21 2018 at 11:05)</a>:</h4>
<p>same</p>



<a name="152323311"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323311" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323311">(Dec 21 2018 at 11:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> for instance I'm looking at <a href="https://play.rust-lang.org/?version=nightly&amp;mode=release&amp;edition=2018&amp;gist=2cdd6791d0a2d82967b4864ab396413a" target="_blank" title="https://play.rust-lang.org/?version=nightly&amp;mode=release&amp;edition=2018&amp;gist=2cdd6791d0a2d82967b4864ab396413a">code like this</a> and was wondering to which region they were mapped, especially since the same lifetime can be seen multiple times, and there are 6-8 regions for this function</p>



<a name="152323324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323324">(Dec 21 2018 at 11:09)</a>:</h4>
<p>it would be good to try to fix this</p>



<a name="152323335"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323335" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323335">(Dec 21 2018 at 11:09)</a>:</h4>
<p>maybe open an issue and tag it A-NLL for now</p>



<a name="152323356"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323356" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323356">(Dec 21 2018 at 11:09)</a>:</h4>
<p>so, say, I was wondering whether the &amp;'a for the return type was the same inference variabla as the first argument</p>



<a name="152323366"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323366" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323366">(Dec 21 2018 at 11:09)</a>:</h4>
<p>ok will do, thanks Felix :)</p>



<a name="152323433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323433">(Dec 21 2018 at 11:10)</a>:</h4>
<p>At this point the way I've been dealing with Q's like that</p>



<a name="152323454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323454">(Dec 21 2018 at 11:10)</a>:</h4>
<p>is staring at RUST_LOG output</p>



<a name="152323457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323457">(Dec 21 2018 at 11:10)</a>:</h4>
<p>for far too long</p>



<a name="152323486"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323486" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323486">(Dec 21 2018 at 11:11)</a>:</h4>
<p>yeah we can do that, but requires a custom rustc build for "regular users"</p>



<a name="152323490"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323490" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323490">(Dec 21 2018 at 11:11)</a>:</h4>
<p>oh right</p>



<a name="152323492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323492">(Dec 21 2018 at 11:11)</a>:</h4>
<p>"sigh"</p>



<a name="152323512"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323512" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323512">(Dec 21 2018 at 11:11)</a>:</h4>
<p>I wonder if we could get our CI to make a debug-build variant of the nightly channel added to <code>rustup</code></p>



<a name="152323556"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323556" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323556">(Dec 21 2018 at 11:12)</a>:</h4>
<p>yeah like the llvm-assertions enabled one, ALT I guess</p>



<a name="152323560"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323560" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323560">(Dec 21 2018 at 11:12)</a>:</h4>
<p>does that exist? An llvm-assertions enabled build?</p>



<a name="152323562"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323562" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323562">(Dec 21 2018 at 11:12)</a>:</h4>
<p>I'm not sure it does, it was talked about at some point</p>



<a name="152323566"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323566" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323566">(Dec 21 2018 at 11:12)</a>:</h4>
<p>if so we might be able to convince T-infra to just fold the two ideas into one build</p>



<a name="152323574"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323574" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323574">(Dec 21 2018 at 11:13)</a>:</h4>
<p>since if you're paying for debug=true, you might also be willing to pay for LLVM assertions</p>



<a name="152323579"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323579" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323579">(Dec 21 2018 at 11:13)</a>:</h4>
<p>but surely did not end up as a rustup channel</p>



<a name="152323587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152323587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152323587">(Dec 21 2018 at 11:13)</a>:</h4>
<p>(the main issue I could imagine is LLVM-assertions causing an early failure and thus causing one to be unable to recreate a problem of interest)</p>



<a name="152334013"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152334013" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152334013">(Dec 21 2018 at 14:33)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> sorry to bother you Felix, do you know of documentation about the NLL mir dump format ? sections are generally named, but not columns, so I was wondering what some of those were. Or should I maybe more simply look for the code that generates it ?</p>



<a name="152334139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152334139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152334139">(Dec 21 2018 at 14:35)</a>:</h4>
<p><span class="user-mention" data-user-id="116113">@lqd</span>  I don't know offhand, sorry. You should probably look for the code that generates them.</p>



<a name="152334238"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152334238" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152334238">(Dec 21 2018 at 14:36)</a>:</h4>
<p>alright, thank you</p>



<a name="152478635"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/152478635" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#152478635">(Dec 24 2018 at 17:54)</a>:</h4>
<p>Merry Christmas to everyone!!!</p>



<a name="154193249"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/154193249" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#154193249">(Jan 02 2019 at 18:56)</a>:</h4>
<p>Meeting today?</p>



<a name="154196405"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/154196405" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#154196405">(Jan 02 2019 at 19:46)</a>:</h4>
<p>I'm around but still in general "catch up mode"</p>



<a name="154196409"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/154196409" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#154196409">(Jan 02 2019 at 19:46)</a>:</h4>
<p>so I could go either way</p>



<a name="154197717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/154197717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#154197717">(Jan 02 2019 at 20:09)</a>:</h4>
<p>I'll add a heading in the paper doc for people to write down any status updates, but I'm OK with no meeting.</p>



<a name="154198048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/154198048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#154198048">(Jan 02 2019 at 20:14)</a>:</h4>
<p><span class="emoji emoji-1f44d" title="+1">:+1:</span> cc <span class="user-group-mention" data-user-group-id="491">@WG-compiler-nll</span> <span class="emoji emoji-1f446" title="point up">:point_up:</span></p>



<a name="156356706"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/156356706" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#156356706">(Jan 18 2019 at 09:56)</a>:</h4>
<p>for people following at home, niko has a new <a href="http://smallcultfollowing.com/babysteps/blog/2019/01/17/polonius-and-region-errors/" target="_blank" title="http://smallcultfollowing.com/babysteps/blog/2019/01/17/polonius-and-region-errors/">polonius post</a></p>



<a name="163910202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/163910202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#163910202">(Apr 22 2019 at 15:08)</a>:</h4>
<p><span class="user-mention" data-user-id="116118">@Matthew Jasper</span> yay <span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span> for <a href="https://github.com/rust-lang/rust/issues/59114" target="_blank" title="https://github.com/rust-lang/rust/issues/59114">#59114</a></p>



<a name="163910253"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/163910253" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Matthew Jasper <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#163910253">(Apr 22 2019 at 15:09)</a>:</h4>
<p><span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span> <span aria-label="party ball" class="emoji emoji-1f38a" role="img" title="party ball">:party_ball:</span> <span aria-label="sunglasses" class="emoji emoji-1f60e" role="img" title="sunglasses">:sunglasses:</span></p>



<a name="163910343"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/163910343" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#163910343">(Apr 22 2019 at 15:10)</a>:</h4>
<p>awesome job :)</p>



<a name="163926545"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/163926545" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#163926545">(Apr 22 2019 at 18:42)</a>:</h4>
<p>Well done Matthew!</p>



<a name="163931979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/163931979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#163931979">(Apr 22 2019 at 19:47)</a>:</h4>
<p><span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span></p>



<a name="169116281"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169116281" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169116281">(Jun 27 2019 at 09:05)</a>:</h4>
<p>okay, embarrassing question time: Who wants to remind me why I'm totally wrong on <a href="https://github.com/rust-lang/rust/issues/62170" target="_blank" title="https://github.com/rust-lang/rust/issues/62170">#62170</a> "match guard is lengthening borrow unexpectedly under NLL" ?</p>



<a name="169172786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169172786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169172786">(Jun 27 2019 at 20:32)</a>:</h4>
<p>isn't that a case for Polonius ?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169172832" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169172832">(Jun 27 2019 at 20:33)</a>:</h4>
<p>à la <a href="https://github.com/rust-lang/rust/issues/47680" target="_blank" title="https://github.com/rust-lang/rust/issues/47680">#47680</a> ?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169189288" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169189288">(Jun 28 2019 at 00:56)</a>:</h4>
<p>yes I think that is <span class="user-mention" data-user-id="116118">@Matthew Jasper</span> 's assertion as well, since they added that as a tag to the issue I fild</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169189306" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169189306">(Jun 28 2019 at 00:57)</a>:</h4>
<p>for some reason I thought this  case wouldn't require going all the way to polonius, but I am too tired to think straight about this right now</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/general%20discussion/near/169203473" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/general.20discussion.html#169203473">(Jun 28 2019 at 07:12)</a>:</h4>
<p>ah right I hadn’t seen Matthew’s tag, I’m just staring at <code>-z polonius</code> bugs in loops at the moment :) (and whenever I see a loop borrowing + killing the same variable + control flow, I think it’s probably a job for polonius more so than NLLs) it’s an interesting thought to try supporting these simpler cases (but as they work in Polonius today, maybe we wait a bit to see how that evolves and then revisit ?)</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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